Welcome to the Community, Jessica. In QuickBooks Online (QBO), you can't bulk import payment terms since there's no option for mapping those during import.
You'll need to edit each vendor manually and add the net terms.
To manually update, go to the All apps > Expenses & Bills > Vendors. After that, select the vendor's name, then click Edit. Scroll down until you find the Additional info section, then click the dropdown menu in the Terms field and select the correct Net.
You can also use a third-party app to bulk update vendor terms for an easier process.
Feel free to comment below if you have more questions about QuickBooks.
