Using classic Outlook for Windows in business environments
If you're the global admin, try it from 365 Admin portal: https://admin.microsoft.com
Click Users (to expand) and click Active Users. You should get something like the following. Click MFA (highlighted).
Clicking that should take you to https://account.activedirectory.windowsazure.com/
You can do bulk update (enable/disable MFA on all accounts) or select your account only to disable MFA.