What is two-factor authentication (2FA)?

Why it matters for agencies

2FA is exactly why sharing a login breaks: codes go to the account owner, not the agency. Partner and user access sidestep the problem because nobody logs in as the client.

The short version

If you're an agency or a client trying to get set up quickly: two-factor authentication adds a second step to login — usually a code from a phone — so a password alone isn't enough to access an account. The practical takeaway is that you should never need to share a password to make this work — every major platform has an official way to grant access, and it can always be removed later.