With the Essentials plan, you do have MFA available to you on a Tenant level under Tenant>Multi-Factor. To have users set up MFA you either need to set MFA to Required, where users will need to set up MFA to complete a login or you will need to enable the “Self Service Account Management” page so users can visit it to set up MFA. So you can set up MFA for any Tenant to make it available to users.
https://fusionauth.io/docs/lifecycle/authenticate-users/multi-factor-authentication
https://fusionauth.io/docs/lifecycle/manage-users/account-management/
In order to change MFA settings at the Application level for enabling MFA on a project by project basis, you would need to upgrade to the Enterprise plan.