I can help you manage users in QuickBooks Online (QBO).
If you want to add a user to your account, you'll have to delete the account first and then add a new one. You can check this article on how many users you can add to your QBO account: How many users can I set up?
Once done, please follow the steps below to add a user:
Click the Gear icon.
Under Your Company, click Manage Users.
In the Manage Users page, click the Add user button.
Select the user type, and then click Next.
Enter your new user's name and email address.
Click Save.
Also, you can visit this article to learn about the types of users you can add and what they can do in QBO: User types in QuickBooks Online.
However, if you'd like to get in touch with our support. Here's how: