If you are the owner of a team, you can configure the accepted login methods for your team members. Go to the Team Settings Panel > Authentication and Toggle the Login methods you want to authorize.
Approved e-mail domain(s)
Another method of authentication is through allowing only email addresses from a determined domain.
Example: if your business e-mail domain is @marketing.com, every person with a @marketing.com e-mail address (e.g., email@example.com, firstname.lastname@example.org) will be able to join your team automatically.
Custom Single Sign-On (SSO)
Finally, only for Enterprises, you can now configure SAML2 based Single Sign On for your company. This allows you to let your staff login using their existing work account. You can integrate Okta, OneLogin, ADFS or any other IdP of your choice.
For more information and setup instructions, go to the section Configure SAML2 based Single Sign On.