How to Turn On MFA in Microsoft 365 for All Accounts

Imagine that an employee's email password shows up in a leaked list or gets typed into a fake page. If the account relies on the password alone, whoever found it can sign in. If the account requires a second confirmation, such as a code on the phone, the story changes. That is what multifactor authentication, or MFA, does. In this article you will see how to turn on MFA in Microsoft 365 and in other accounts, and where to start.

What MFA is and why it helps

MFA means asking for two or more forms of verification to sign in. Besides the password, the person confirms something only they have or are, such as a phone or a fingerprint. According to Microsoft's documentation, the second factor is not easy for an attacker to obtain or copy. CISA, the US cybersecurity agency, puts it the same way: even if the password is stolen, the attacker cannot complete the second step.

MFA does not replace good passwords or caution with scams. It lowers the risk of an account being accessed just because a password leaked.

Where to start turning on MFA

You do not need to change everything in one day. A simple order:

1. Start with email. The email account is often the way to reset passwords on other accounts. If it falls, the others are exposed.

2. Move on to accounts that hold company data: Microsoft 365, financial systems, file storage and the brand's social media.

3. Prioritize people with the most access, such as administrators and owners, before extending to the whole team.

CISA's recommendation is to turn on MFA on every account or app that offers it.

How to choose the second factor

The most common methods include an authenticator app, biometrics (such as Windows Hello), a security key or passkey, and also SMS codes. Microsoft lists all of them as methods available in Entra. In practice:

• Authenticator app: a good starting point for most teams, because it works on the phone people already have.

• Biometrics and security keys: good options when the company wants less typing of codes day to day.

• SMS: better than no MFA, but when an alternative exists, prefer one of the methods above.

How to turn on MFA in Microsoft 365

In Microsoft 365, identity is handled by Microsoft Entra ID. According to Microsoft, Entra security defaults turn on Microsoft Authenticator for all users and are the simplest way to begin. When the company needs more specific rules, such as requiring MFA only in certain situations, Conditional Access offers finer controls.

Some features depend on your plan, so check what your license includes before planning the rollout.

How to prepare your team

• Warn people ahead of time and explain the reason in plain language.

• Show the first-time setup step by step, ideally with someone from IT available to answer questions.

• Decide what happens when someone changes phones or loses the device, so nobody is locked out.

• Pair MFA with training on scams. In our article on QR code scams in Teams, we show how a second factor helps when a password is handed over by mistake.

Source

Information checked on October 23, 2026 in the Microsoft Entra multifactor authentication overview on Microsoft Learn, and on the Turn On MFA page from CISA (Secure Our World).

Need help?

WRA IT helps companies roll out MFA, security defaults and Conditional Access in Microsoft 365, calmly and without slowing down the team's work. Get in touch at www.wra.com.br.