What are the steps to do this if you do not use the Products/Services portion for invoicing? Meaning that when I'm on the credit memo screen, I cannot choose a product/service as the option to do so isn't there. 

I have the bad debt expense in my chart of accounts already.

But I cannot find a place on the credit memo to tie that to this customer's account so that I can clear the $187 portion of the invoice they did not pay, and move it to bad debt expense.

FWIW, we are cash basis and I'm using QBO. 

Thank you.