You don't have to show any receipts or proof of expenses on your tax return. Just claim the legitimate expenses.
If you get audited you will have to show records of the expenses. You should be keeping detailed written or computerized records of all your expenses. Also keep a copy of the Cash App records or statements showing the payments. Your accounting records plus the records of the payments should be sufficient to support the expenses in an audit. You might want to consult a local CPA for advice on how to keep proper records for your rental properties.
