Thank you for joining the thread. Let me help you fix your issue with the Manage users section to enable you to add users in your QuickBooks Online (QBO) account.
This section is always available in QuickBooks Online. If you’re unable to locate the section, I suggest performing some basic browser troubleshooting to help isolate and fix the problem.
Here are the keyboard shortcuts to open a private browser:
Google Chrome: press Ctrl + Shift + N
Mozilla Firefox: press Ctrl + Shift + P
Microsoft Edge: press Ctrl + Shift + P
Safari: press Command + Shift +N
If it works, kindly proceed with clearing the cache. There are times that browser is loaded up with data that affects the performance of QuickBooks.