Does Finalising Bridal MUA requires paperwork?

Guys I have finalised a MUA for my wedding, got to know about her via Insta. And she is asking for 30% advance payment which is non refundable. All that is fine but since there are a lot of scams going on, Is there something that states as a proof of this? Like an email or something? She is a freelancer, so she said she can give it to me in written, idk if that means the bill or just a note on paper. Like hypothetically she didn’t show up on the wedding date(bhagwan na kare), what can i ask her so that she can be held accountable.