Right now, QuickBooks Online doesn’t have an option to set up security questions. In the meantime, you can delete your former administrator as a user in your account. You can follow the steps in this article to remove him or her:

https://community.intuit.com/articles/1442990

Resolution for 'article to remove issue: 'I want to change my security questions but when I select this it says I am forbidden. As the Master Administrator, why am I not allowed to do this?' available: Yes.

The article to remove 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 article to remove issue yourself by looking for a resolution described in the article. If it is a complex article to remove issue or you are unable to solve the issue, you may contact us by clicking here or by using other article to remove support options.

For more information about resolving issues related to article to remove in Quickbooks/QBO or to get support for the issue 'I want to change my security questions but when I select this it says I am forbidden. As the Master Administrator, why am I not allowed to do this?', click the link below: