I can guide you on how you can record a customer payment in QuickBooks, tonyjen609.
If you receive the payment right away, you can use a Sales Receipt.
If you'll receive the payment at the later part, you can use the Invoice.
I've got you an article on how to record a customer payment. This will provide you more information and detailed steps.
You're now able to record the payments to QuickBooks Online tonyjen609.
If other questions arise, you can tag me in a comment. I'll be sure to get back to you. Thanks!