To edit an invoice that already exists: Open the invoice you want to change and then manually change the terms. Using the drop down menu pick the terms you want for the invoice. It will show you a drop-down menu of the terms you have set up in QBO. If the terms you want are not there you will need to add them (it's the first option it should say +AddNew and then it will show the other terms which are already set up).
To edit the CUSTOMER so that their terms are updated for all new invoices, go to CUSTOMERS. Click on EDIT (small button right-hand side). Go to PAYMENTS and change the Terms using the drop down menu which provides you with the terms you currently have set up.
