I want to edit the payment duration in the invoice for example net 30 or net 60

You have me to help you modify your preferred invoice terms, usermamafooders.

Let me guide you with these steps:

1. From the Gear icon, select Account and settings.
2. Go to the Sales tab.
3. Click the pencil (edit) icon on the Sales form content section.
4. Modify your Preferred invoice terms.
5. Click Save and then Done.

Also, if you want to send an online invoice, you can check this article for more information: Take and process payments in QuickBooks Online.

There you have it. Keep me posted if ever you need help. I've got you!