Pleased to see you here in the Community, @Wequips.
I'm here to share information about deleting tax agency in QuickBooks Online (QBO).
Are you referring to the Sales Tax Agency in QBO? If so, currently, QBO doesn't have the option to delete a Tax Agency. However, you can deactivate it, and I'm happy to show you how:
1. Go to Taxes menu on the left pane.
2. In the Sales Tax Center, go to the Related Tasks section and select Add/edit tax rates and agencies.
3. Choose a tax agency name then select Deactivate.
4. Select Continue on the dialog box.
If you don't see the settings above, you may be using the Auto Sales Tax feature. But good news! Here's how to make a tax agency inactive if you're using Auto Sales Tax:
1. Go back to Sales Tax Center, then click Edit sales tax setting.
2. Go to the Action column and from the Edit drop-down, select Make inactive.
3. On the window that pops up, select the Make Inactive button.
You can refer to this article for more information (scroll down to Make a tax agency active/inactive): https://community.intuit.com/articles/1567657.
That's it. If you're referring to something else, please let me know. I'm always here to help you out. Wishing you continued success!