Good day, Amira.

There are several ways on how to edit or adjust your invoice payment terms in QuickBooks Online. From the invoice itself, you can adjust the invoice payment terms. However, this only applies to this specific invoice. 

If you'd like to change the default setup you'll need to go into settings. Here's how you can do it:

1. Click the Gear icon.
2. Select Account and Settings.
3. Click the Sales tab on the left and then click the pencil icon for Sales form content.
4. Once you make a selection, your preferred invoice terms are automatically applied to all invoices going forward.
5. Click Save then choose Done.

I've attached screenshots below for you to see it.

Keep me posted if you have any questions about QuickBooks.