We can set your Organisation's users to enforce logins via Single Sign On (SSO). If you want to use this feature please get in contact with support who can enable it.
See this related article on using SSO.
Enforced SSO (any provider)
If this feature is enabled, after logging in with their username and password users will see the below view. They will then need to select one of the providers to be able to login to their account
Future logins with SSO will skip this step but any attempts to login with username and password will redirect the user to the above.
If the user has no existing SSO associations they will be able to create a new one (as described above) but then no further SSO associations will be able to be made.
If the user already has any existing SSO associations they will only be able to log in using these existing SSO associations, and will not be able to create new ones.
In this example, the user has 2 existing associations they can use to log in, but cannot create any new ones:
Checking SSO Setup
Administrators can see via the user list on Admin Settings which users have SSO enabled via the user tags that are automatically added to accounts with SSO.