Stolen or weak passwords are behind a large share of breaches, so two technologies aimed squarely at that problem, single sign-on and multi-factor authentication, have become foundational. They solve different parts of the same problem and work best together.
Single sign-on, or SSO, lets people log in once to a central identity provider and gain access to many applications without a separate password for each. This reduces password sprawl, the dozens of weak, reused passwords that plague organizations, and centralizes control: access can be granted or, crucially, revoked in one place when someone leaves. Fewer passwords, managed centrally, is a security gain, not just a convenience.
Multi-factor authentication, or MFA, requires a second proof of identity beyond the password, something you have, like a phone or hardware key, or something you are, like a fingerprint. The point is that a stolen password alone is no longer enough to get in. MFA is one of the single most effective controls against account takeover, which is why frameworks, insurers, and regulators increasingly expect it.
SSO reduces the number of passwords and centralizes control; MFA makes the remaining login much harder to defeat. Applied together, especially with phishing-resistant MFA, they close off the most common path attackers take. For any system holding sensitive data, they are close to table stakes now.
Fewer passwords, and none of them enough alone.
This is general educational information, not specific security, compliance, or legal advice for your systems.