Let me share some details in adding a transaction.
In QuickBooks Self-Employed, we're unable to assign a payer when manually recording a transaction. You'll want to add it in the description field instead. Also, if you have a receipt, you can attach it to the transaction. For the detailed steps, here's how to manually add transactions in QuickBooks Self-Employed.
If you're using the mobile app, we can fix it by simply uninstalling and reinstalling it if the Payer was gone.