Not “sent”. Provably received.
The tax audit comes years later, and what counts then is a document rather than a memory. Six things stay behind for every return.
Transferticket
The number issued by the tax authority. Without it, all you have is a claim that you sent something.
Submission protocol
The original protocol is kept unchanged, ready to download and hand to your tax adviser.
Hash of the sent file
A fingerprint of what went out, so years later you can still prove it was the same file.
Figures as locked
The time, the person and the figures as they stood. Later changes to entries do not touch this return.
Amendment history
The sequence number rises, the link to the amended return is kept, and the original is never deleted.
Test submission
Practice runs are marked separately, so someone new can try it without worrying.
What gets examined is not the figure but where it came from.
The usual question is where a number came from. What helps at that point is not an explanation but the document as it stood when the return was locked.
So the figures freeze at the moment of locking, and the file sent is stored alongside the protocol received. Later corrections in the ledger do not move a return already filed.
Three rules for handling records
Deletions stay traceable
Data is never physically removed. Who changed what and when is kept with it.
Errors are not hidden
When a submission fails, the return code and message are shown as they are, never dressed up as success.
Practice stays out of the real list
Test submissions are marked separately and never appear alongside genuine returns.