Why keep proof at all?
Most stress comes from one thought:
- “If someone asks me later, can I explain these numbers?”
If your records are simple and consistent, you can.
This is practical guidance, not legal advice. Rules and requirements can vary, so when in doubt, check official sources or a professional.
The simple monthly folder
Create one folder per month (on your computer or cloud) and keep a small set of files.
Example:
2026-02/
What to keep (recommended)
1) Payment proof
Keep something that shows you received money:
- bank statement screenshot/PDF
- payment provider receipt (if you use one)
2) Invoices (if you issue them)
If you send invoices to clients, save:
- the invoice PDF
- or a copy of the invoice email
3) Contracts / agreements (when relevant)
If you work with recurring clients, keep:
- a signed contract
- or an email thread that clearly confirms scope and price
4) Notes for unusual situations
If something is unusual, keep a tiny note (a text file is fine):
- refund
- correction
- partial payment
- transfer that is not business income
5) Exchange rate reference (for foreign income)
If you receive USD/EUR, save something that supports your rate choice:
- a link or screenshot of the official rate
- or your calculation note
Guide: /en/blog/foreign-income-and-exchange-rates/
How Taxocat helps
When your income entries are tidy:
- your month is easy to review
- you can finish a declaration in Manual or Auto mode
Read:
A practical rule
Keep enough proof so that if you look back in 6 months, you can still understand every income entry.