SIGNL4 does support SSO and MFA (multi-factor authentication) if you decide to use either Microsoft or Google sign-up for SIGNL4. In this case, SIGNL4 just piggybacks on any MFA you have enabled for your Microsoft, Google or Apple account. SSO is done through the authentication of Microsoft, Google or Apple.
Please, note that the SIGNL4 native authentication method does currently not offer MFA. If you wish to change your authentication methods you would need to terminate your current subscription and sign up again.
Here is how to enable Microsoft Azure AD for SSO and MFA in SIGNL4: https://www.signl4.com/blog/authorizing-signl4-as-enterprise-app-for-users-in-azure-ad/