I googled and found a form with the information they would want and had my nanny sign it.

Example:

https://www.24hourflex.com/fsa/Dependent-Care-Receipt

I think this is from a specific company for their FSA but easy to doctor.

What kind of documents do you submit to get DCFSA reimbursement for your nanny? I use Poppins Payroll, but the paystubs do not say that she's providing child care or show my daughter's information. If I submit paystubs plus the nanny contract, is that sufficient?