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Although there are MFA methods mentioned in user setup, this is not how MFA is enabled. MFA is enabled through a permission set with a specific permission that enforces an MFA method to log in. Users can define an MFA method through their user profile, or can be prompted to set up a method once MFA is enforced.
The following is the simplest one straightforward method to enforce MFA and assumes that a Single Sign On (SSO) method is not implemented (for example, enforced SSO through Office 365).
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