To approve an expense, simply click on the "Approve" button of the expense in the list of "To review" expenses. The expense will move from the "To review" tab to the "Approved" tab. It will not be possible to modify it anymore (unless you click on "Revert decision"). If you have connected an accounting software, we will export the expense automatically. The expense data will remain in Completed tab, so you can always access the data.