Do you mean in a company file?  If so:

Company

Set up users & passwords

Set up users

Highlight the user, press DELETE on […]

Resolution for 'authorized users issue: 'How do I delete Quickbooks Desktop Pro 2016 authorized users?' available: Yes.

The authorized users issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the authorized users issue yourself by looking for a resolution described in the article. If it is a complex authorized users issue or you are unable to solve the issue, you may contact us by clicking here or by using other authorized users support options.

For more information about resolving issues related to authorized users in Quickbooks/QBO or to get support for the issue 'How do I delete Quickbooks Desktop Pro 2016 authorized users?', click the link below:

Details