Create a customer invoice and post it.

Create customer payment, choose 'Send' as the payment type, you can see list of invoices for the selected customer, add the payment amount and click on the 'Confirm' button.

If the added amount is less than the total invoice amount, an 'Invalid' warning popup will appear.

Allocate payment amount with the invoice amount and click on confirm button. Invoice status will be changed with partially paid.
Click on the 'Invoice' smart button to view the adjusted invoice.

Partially paid invoice with adjusted paid amount.

Create vendor payment, choose 'Send' as the payment type, you can see list of bills for the selected vendor, add the payment amount and click on the 'Confirm' button.

If the added amount is less than the total bill amount, an 'Invalid' warning popup will appear.

Allocate the payment amount with the invoice amount, then click on the Confirm button.

Bill status will be changed with partially paid. Click on the 'Bill' smart button to view the bill.

Create another payment with same customer, you will see total amount and outstanding amount of the bill. Add the bill amount and click on confirm.

Bill has been fully paid. Also status will be changed from partially paid to paid.

You can adjust advance payment with invoice/bills. click on add button from outstanding credits in the invoice.

After that one wizard opens, enter the custom amount in the 'Amount Currency' field and click on 'Add Payment' button.

You can see adjusted advance payment with custom amount in the invoice.

Here, you can view the paid amount date, and count.