Short answer: your accountant needs a document or an explanation for every transaction of the month, your outgoing invoices and any special items — early enough to file the VAT return on time. Neat folders help, but they aren’t the standard. The standard is that no transaction is left open at month-end without someone knowing why.
This guide is written for businesses in Germany, where the tax advisor (Steuerberater) often does the monthly bookkeeping too. Elsewhere, the logic carries over: find the due date of your VAT or sales-tax return and work backwards.
What your accountant needs every month
Your accountant books your bank transactions, not your folders. Every payment on the business account, the company card or PayPal needs a document — or a one-line reason why there isn’t one:
- Supplier invoices: the vendor’s invoice, not the payment confirmation — without a proper invoice, there’s no input VAT deduction (Section 15(1) UStG).
- Transactions from every account: business account, card, PayPal and other payment providers. Many tax firms get bank data directly — ask which accounts they’re missing.
- Outgoing invoices: all invoices, credit notes and cancellations. Invoice numbers must be sequential and unique (Section 14(4) UStG); gaps trigger questions.
- Explanations for transactions without a document: transfers between your own accounts, private payments, loan instalments.
- Substitute receipts (Eigenbelege) for genuine gaps, each stating why the original doesn’t exist.
- Business meal receipts (Bewirtungsbelege) with the occasion and attendees, restaurant bill attached.
- Travel expenses: hotel and transport receipts plus a report with purpose, destination, start and end of the trip — see travel expenses.
- Special items: private use of company money or assets, new loans, leases, larger purchases and, if your accountant runs payroll, staff changes.
Contracts go over once: with the loan agreement and repayment schedule, your accountant can split every instalment into interest and principal.
The deadlines that set your monthly rhythm
The rhythm comes from the German advance VAT return (Umsatzsteuer-Voranmeldung). It is due by the 10th day after the end of the filing period, and so is the payment (Section 18(1) UStG). The default period is the calendar quarter. If last year’s VAT liability exceeded €9,000, you file monthly; at €2,000 or less, the tax office can exempt you from advance returns altogether.
A permanent deadline extension (Dauerfristverlängerung) moves filing and payment back by one month on application (Section 46 UStDV). Monthly filers pay for it with a special prepayment of one eleventh of last year’s prepayments (Section 47 UStDV), due by 10 February in later years and credited against the December payment (Section 48 UStDV). Quarterly filers pay none. Details: Dauerfristverlängerung (German).
A real calendar example: the return for September 2026 would be due on 10 October. That’s a Saturday, so the deadline moves to Monday, 12 October (Section 108(3) AO). With the extension, it’s Tuesday, 10 November.
| Situation | VAT return due | Documents sensibly with your accountant |
|---|---|---|
| Monthly, no extension (September 2026) | Mon, 12 October 2026 | in the first week of October |
| Monthly, with extension (September 2026) | Tue, 10 November 2026 | by the end of October |
| Quarterly (Q3 2026) | Mon, 12 October 2026; with extension 10 November | still month by month, so nothing piles up |
The last column is a rule of thumb. Your accountant needs time to book and ask questions, so agree on a fixed cut-off day and make it a recurring calendar event.
Handoff options compared
The route is mostly decided by the software your accountant uses. Four are common in Germany:
| Route | How it works | Fits when … | Watch out for |
|---|---|---|---|
| DATEV Unternehmen online | Documents go straight into your accountant’s DATEV data: browser upload (Upload online), app photo (Upload mobil) or email forwarding (Upload Mail). | your accountant works with DATEV and you set up access together | Upload Mail only accepts authorized senders, and no pure XRechnung (XML) |
| Accountant login in Lexware Office or sevDesk | You invite your accountant into your app; they see documents and bookings and pull the data into their software. | you already write invoices or collect receipts there | agree who books and who matches, or work gets done twice |
| ZIP of PDFs plus a transaction list | All documents of the month plus a spreadsheet of every transaction with its status, sent as a link or by email. | there is no shared platform, or you have few transactions | the list must include transactions without a document, or nobody sees the gaps |
| Paper binder (Pendelordner) | A binder of sorted paper receipts travels to the accountant and back every month. | almost all your receipts are paper, such as till receipts | emailed invoices would have to be printed; an e-invoice can’t be meaningfully filed on paper |
In DATEV Unternehmen online, Upload Mail lives under Belege → Konfiguration → Upload Mail → Konfigurieren (the interface is in German). You add authorized sender addresses, confirm each one by email and get a separate target address per document type, such as incoming invoices (Rechnungseingang) or outgoing invoices (Rechnungsausgang). It accepts PDF and TIFF, including ZUGFeRD invoices; a pure XRechnung XML file goes in another way, for example via Upload online (DATEV help: setting up Upload Mail (in German)).
In sevDesk, you invite your accountant under Erweiterungen → Integrationen → Steuerberater einladen. They get a login in sevDesk’s free tax-advisor portal, see your bookkeeping data in real time and download the DATEV export themselves (sevdesk help: inviting your tax advisor (in German)). In Lexware Office, tax-advisor access is part of every edition, and either side can send the invitation (Lexware Office: tax advisor access (in German)).
The paper Pendelordner, literally a “shuttle binder”, is fading for a simple reason: many invoices arrive as files anyway, so printing and carrying them doubles the work. With an e-invoice, the XML file is the legally relevant original, not a printout. And while the binder sits at the tax firm, you don’t have your own records.
What to agree with your accountant up front
- Route and cut-off day: which route, and by which day of the month.
- Who books: you, with your accountant reviewing, or your accountant alone.
- Which accounts your accountant receives directly, and which exports you supply.
- Shared labels: the same words for exceptions on both sides — “private”, “substitute receipt”, “requested” — and one question list per month.
- E-invoices and the extension: how the XML files get over, and whether a deadline extension shifts your cut-off by a month.
Completeness beats tidy folders: the exceptions list
Folder structures are a matter of taste; completeness isn’t. The most important file of the month is the list of all transactions with a status on every line — and each line without a document needs a named reason:
- Requested on … — the vendor has been asked, the invoice will follow.
- Substitute receipt — the original can’t be obtained, the Eigenbeleg is attached.
- Private — a private expense paid from the business account, or the other way round.
- Transfer — money moved between your own accounts, evidenced by the other account’s statement.
- Contract on file — loan instalment, lease or rent; the contract was handed over earlier.
Build it from your bank’s CSV export plus a “status” and a “comment” column. How to match line by line is covered in the invoice reconciliation workflow.
Documenting exceptions properly
Substitute receipt: payee, date, amount, business purpose, the reason the original is missing, plus the date and your signature. It supports the business expense but not the input VAT, which needs a proper invoice. Before writing one, try for a copy from your mailbox, the vendor portal or the vendor.
Business meals: German income tax law requires written details of place, date, attendees, occasion and amount (Section 4(5) sentence 1 no. 2 EStG). For a restaurant meal, occasion and attendees are enough, with the bill attached. 70 percent of the reasonable, documented cost is deductible. More under meal receipts.
Private items: label them, don’t hide them. For a sole proprietor they become a private withdrawal or contribution. A GmbH, the German limited company, has no private withdrawals; private payments usually go through the shareholder’s clearing account.
File names and folders, briefly: one folder per month with incoming, outgoing and exceptions, and names like 2026-09-14_Vendor_119.00.pdf. That the date and amount match the transaction matters more than any structure.
The month-end checklist
- Pull the transactions of every account, complete to the last day of the month.
- Match each transaction to a document and replace payment confirmations with real invoices.
- Chase missing invoices: mailbox, vendor portal, then the vendor itself — and note “requested on …”.
- Complete business meals with the occasion and attendees.
- Settle trips: purpose, destination, start and end, plus hotel and transport receipts.
- Label the exceptions: private, transfer, contract, substitute receipt.
- Check outgoing invoices: credit notes and cancellations included, no gaps in the numbering.
- Remove duplicates: an invoice from both email and portal goes over once (see preventing duplicate invoices).
- Report special items: new contracts, loans, larger purchases, staff changes.
- Hand over before the cut-off and answer your accountant’s questions in one batch.
One extra tip: photograph thermal till receipts right away, before the print fades.
Common mistakes: why documents bounce back
Single documents usually bounce for a handful of reasons, such as a payment confirmation instead of an invoice or a missing mandatory detail. The German page receipt rejected by the tax advisor (German) covers the seven most common ones. The handoff itself has its own traps:
- Documents without a list: a pile of PDFs but no overview of what’s open, so the gaps surface weeks later during booking.
- Everything at year-end: the VAT returns still get filed, just without the input VAT from missing invoices — and spring turns into a hunt for receipts more than a year old.
- Unlabelled private payments: each one becomes a question.
- Scattered answers and double submissions: receipts by messenger, email and portal — nobody knows what’s missing, and one invoice may get booked twice.
Year-end and retention
Before the annual accounts (Jahresabschluss), your accountant often sends a list of missing documents — a short one if you’ve handed over cleanly every month. Still, review the whole year once in December: what is still “requested”, which substitute receipts are missing? For working through a long list, see finding missing receipts before the annual accounts (German).
Handing documents over doesn’t end your duty to keep them. In Germany, accounting vouchers, invoices included, must be kept for eight years (Section 147(3) AO, Section 14b UStG), books and annual accounts for ten and business correspondence for six. The period starts at the end of the calendar year in which the document was created, so an invoice from 2026 can be deleted in 2035 at the earliest. Agree with your accountant where the originals live — the obligation stays with you.
How belege.ai handles the handoff
belege.ai treats your bank transactions as the to-do list. For each payment, its AI agent finds the matching invoice in your connected mailboxes or, for many vendors, the customer portal, checks it and attaches it to the transaction. It asks via Telegram only when it can’t finish a case alone, such as a paper receipt or a two-factor code, and creates a substitute receipt only with your explicit OK. More under match receipts.
The handoff routes you can agree with your accountant:
- Monthly ZIP: for example
Firma_Buchhaltung_2026-09.zip, with one CSV per bank account — from date and amount to status, linked documents and comment — plus folders for documents, substitute receipts, business meal receipts and unassigned files. - Share link: your accountant opens it without logging in and downloads the package. You can revoke it at any time.
- DATEV Unternehmen online: belege.ai sends the documents as PDFs to your Upload Mail address. You authorize belege.ai’s sender address in DATEV; a test document goes first, and the rest follows once it has arrived.
- Lexware Office and sevDesk: by default, the PDF lands in the Lexware Office document inbox (Beleg-Eingang); in sevDesk, the default is a booking proposal that still needs approval.
- Accountant access: you can invite your tax firm with its own role, so it sees transactions and documents directly.
There’s no mandatory approval step before the export: checked matches are applied directly, and the export shows each transaction’s status, including those still missing a document. For DATEV-based setups, see invoice automation software with DATEV export.