Hello there, @marina12.
Currently, we're unable to delete payment terms in QuickBooks Online (QBO). Though, we can make them inactive to hide.
Here's how:
- Go to the Gear icon.
- Under Lists, select All Lists.
- Choose Terms.
- Click the Report drop-down arrow, and then choose to Make inactive.
I've also added this article about adjusting invoice payment terms in QBO: How to adjust invoice payment terms.
Leave me a comment below if you have other questions. I'm more than happy to help. Take care!