The journal: every financial event that has reached the books.
Three states, and one of them is locked
Draft has no effect on the books and is freely editable. Posted takes a number and a security stamp and never changes again. Reversed means an opposing entry has cancelled it.
A posted entry is not edited or deleted. There is no exception.
Correcting means reversing
To fix a mistake you reverse the entry: a new entry is created with the lines inverted, and then you post the correct one.
You end up with three entries in the journal rather than one, and that is deliberate: the books have to show what happened, not a tidied-up version of it.
The number and the stamp are made at posting
An entry takes its number when it is posted — not when the draft is created. Alongside it a security stamp is generated, chained to the previously posted entry.
Which means tampering with an old entry directly in the database breaks the chain and can be detected.
Most entries are not written by you
Issuing an invoice, recording a payment, confirming a store order, clearing a cheque and selling a course all post their own entries. Manual entries are for the rest: adjustments, depreciation, and anything that does not enter the system elsewhere.
An automatic entry is posted like any other — which means it too can only be corrected by reversing it.