In case you have yet to communicate the upcoming MFA requirement to your Salesforce users, here is an email template I used to email to my Salesforce stakeholders and users.
Subject: Multi-factor authentication needed for you to log in to Salesforce on February 1st, 2022
On February 1st, 2022, our internal team will enforce multi factor authentication for users who log into Salesforce directly. These Salesforce users will be required to log in via our SSO provider. If you currently log in via our SSO provider, ignore this message.
Why is this happening?
On February 1st, 2022, Salesforce will require customers to implement MFA. Our internal team has rolled it out to a small group of users, but we will enforce it for all users who log into Salesforce products through the user interface.
Are you having trouble logging in?
Go to insert Slack or Teams channel and let us know the steps you took before you got the error.