As threats against user credentials grow more common, it's increasingly important to implement strong security measures that safeguard your Salesforce data. To enhance the security of your user accounts and better protect against threats like phishing attacks and credential stuffing, we strongly recommend enabling multi-factor authentication (MFA).

For customers with Lightning Experience or Salesforce Classic, we’re here to help with the new Multi-Factor Authentication Assistant — your central hub for delivering MFA to your users. It’s available from Setup, in Lightning Experience only.

The Assistant guides you through a recommended process for a successful rollout — from evaluating requirements and planning your project to implementing MFA, launching it to users, and driving adoption. The process is organized into three phases: Get Ready, Roll Out, and Manage. Each phase includes a set of suggested steps, with supporting resources and tools to help customers take action. 

For full details, check out "Meet the Multi-Factor Authentication Assistant" in Salesforce Help (https://help.salesforce.com/articleView?id=mfa_mfa_assistant.htm).