A warm welcome to the Community, kernowizz.
Changing the invoice payment terms is easy and I'll be glad to show you how. You can set the 7 days for invoice payment terms in QuickBooks through the Account and Settings section.
- Click the Gear icon at the upper right corner and choose Account and Settings.
- Select the Sales tab in the left panel and select Sales format content.
- Click the drop-down arrow and select Add new.
- Enter payment term Name and number of days.
- Hit Save.
That's it! You can go through this article for the steps in editing and setting up payment terms in QuickBooks Online: How to Adjust Invoice Payment Terms in QuickBooks Online.
You can always come back to the Community if anything may arise while working in QuickBooks Online. I'd be glad to help. You have a wonderful day!