Most reimbursement trouble isn't about the money. It's about the missing piece: the receipt with no explanation, the amount with no event, the request you can't process without asking somebody something. A form fixes that at the door, and it doesn't need to be fancy. It needs the right fields.
Here's every field mine had, and the question each one prevents.
Their name and email
Obvious, but the email matters more than it looks. It's how you tell them "approved, it's on the way" without hunting them down, and it's how "did you get my receipt?" stops being a thing people ask you at pickup.
What was this for, as a list they pick from
This is the single most valuable field on the form, and most groups get it wrong by making it a blank box. A blank box gets you "stuff for the thing." A dropdown with your actual events gets you Fall Festival, every time, spelled the same way, connected to the same budget.
Put your events and ongoing budgets in a list. Add a "something else, I'll explain below" option for surprises. Your future self, staring at the books in June, will be so grateful.
The date on the receipt
Not today's date. The date they actually bought the thing. Your form already records when it was submitted, but the receipt date is what tells you whether the purchase fits your deadline and which month it belongs to. Label it clearly: "the day you bought it, not today."
The amount
The exact total from the receipt. Ask for a number and only a number, or you'll get "about forty dollars," and "about" is not a thing you can put in a ledger.
What they bought, item by item
Here's the one nobody warns you about: a card slip showing a total is proof someone paid, not proof of what they paid for. "Cups, plates, napkins" beats "Target." Say that right on the form. A receipt showing only a total is the number one reason a request comes back with questions, and one line of help text prevents almost all of it.
How they'd like to be paid, and where to send it
Check, Venmo, whatever your group actually uses, plus the address or handle to send it to. Without this you'll pay everyone the slow way, or trade three messages to learn a Venmo handle you could have collected up front.
Anything else we should know
An optional catch-all. Most people skip it. The ones who don't will hand you exactly the context you'd otherwise have to ask for: "the rental place charged a deposit, it's already refunded." One optional box, entire conversations saved.
The receipt photo, and the catch nobody mentions
If your form is a Google Form, know this before you add a file upload question: Google requires anyone uploading a file to be signed in to a Google account. At a school, where everyone lives in Google already, that's a non-issue. In a neighborhood group where half your volunteers guard their phones like dragons, it can be a real wall.
Two ways through. Either accept the sign-in because your people won't mind, or skip the upload question and have volunteers email you the receipt instead, with everything else still arriving through the form. And if you build the form yourself, put the upload question last. That way, if your group hates the sign-in, you can delete that one question without touching anything else.
Keep the whole thing under a minute
That's the real test. A volunteer standing in a parking lot should be able to finish your form before their car warms up. Every field above earns its place. Anything else you're tempted to add probably doesn't. The shorter the form, the sooner people fill it in, and the fewer receipts die in a jacket pocket.