To give users a better end-user experience, you can combine the registration of Multifactor Authentication with Self Service Password Reset (SSPR) so that users only have to provide this information once for both services when they login for the first time.
Microsoft 365 - Enable combined registration of MFA and SSPR
Go to User-->User settings-->Choose the setting "Manage user preview settings".
Under the option "Users can use the combined security information registration experience" choose "All" and then click "Save". At the next login via the web portal users should be prompted if they have not setup MFA/SSPR. You can also send users to the following page to setup their security info: https://aka.ms/mfasetup.