I can help you enter additional details of your client's transaction, jcrooter1.
QuickBooks Online has an option to enter checks that allows us to enter a Check No. and Date received. For QuickBooks Self-Employed, if we are using an invoice in recording client transactions we can manually mark it as paid and enter the payment in the Transaction page. From there we can enter the Check # and the Date we received in the Notes field.
Here are a few articles that help us in categorizing transactions and other ways in receiving payments.
Let me know if you need anything else. Thanks!