01Company policy, checked before anyone approves
Each category has its limit, a receipt is required from the amount you choose, and an expense has a deadline. The check runs as the expense is submitted, so the approver sees the result, not a pile of receipts.
Your categories, your limitsName a category in each language, give it a limit and a default VAT rate, and require a comment where it matters, such as who the client meeting was with.
A flag, not a wallAn expense over a limit or past the deadline is not blocked. The approver sees exactly what is wrong and decides.
Purpose and projectAsk for the purpose of every expense and tag it with a project, so nobody has to ask what it was for.