To edit your cash transactions, tap Accounts > select your Cash Register account > under Transactions > View more > find the specific transaction.
Once you open the transaction, you'll see a detailed audit trail, as to who updated the transaction and when, alongside the original and changed values.
On this screen, you can change the following:
Category (change or add)
Receipt (change or upload)
Add tags
Add note
VAT (change or add)
Edit transaction.
All changes you make are automatically saved and displayed in your cash register.