If your organization has requirement to enforce SSO log in (i.e. you need your users to log in to OptiSigns account with your Microsoft Azure AD, or Google GSuite account) where you can enforce 2FA, password policies, etc.
To do so, you can go to Account Preference page:
Drop down Enforce SSO and select Microsoft AD or Google GSuite.
That's it, this will enforce all users who invited to your account to use Microsoft AD or GSuite login.
If user who are invited and tried to sign up another way than the one you enforced.
They will receive an error:
Notes: You will have to use official https://app.optisigns.com/ to log in to enforce SSO. You cannot use custom domain with Enforce SSO, as custom domain URL do not have SSO Log in.