Can I apply a payment to an invoice after posting?

Hi there,

QuickBooks Online makes it easy to record a payment and I'd be glad to show you how. To do this, follow the steps below: 

1.     Select the Create ⨁ icon, then select Receive Payment.
2.     Select the name of the customer from the drop-down menu.
3.     From the Outstanding Transactions section, select the transactions that you’d like for QuickBooks Online to calculate. As you select these items, the payment total will change.
4.     Select your payment method.
5.     Enter the Reference no. and Memo if applicable.
6.     You can either deposit the money to your checking account or to the Undeposited funds account.
7.     Select Save and close.   
    
   For more information on recording payments, I encourage you to check out this helpful article from our Community: Record a customer payment. Let me know if you have other questions. I'm here to help.