If you are looking to credit an invoice because one of the previous invoices of the client is overpaid, please follow the instructions below on your instance.
1. Go to the "Invoice" tab of the lateral menu and click the section "Accounts Receivable". Once there, click the tab "Payments" to update the invoice that has an overpayment. Type the amount paid under the column "Update Payment".
2. Once you have set the amount, under the section where you added the amount paid, a status will appear, select the option "Hold" and click the button "Submit".
3. Due to the change you made, the invoice will be under the tab "Disputed/Partial", which is at the top of the page. Use the filter to sort by company and locate the invoice you updated as overpaid. In the section "Manage Mispay" you will select the invoice that you would like to be applied to.
4. Once you have selected the invoice to which the extra payment will be applied. Click the button "Save". Keep in mind that the amount of the invoice to be paid must be greater than the amount of the extra payment, so as not to have negative amounts.