Open Outlook for Android. The icon looks like this:
If you haven't already, you can download Outlook for Android from the Google Play Store.
Tap Get Started if it's your first time.
Or, go to Settings > Add Account > Add Email Account.
Enter your email account password and tap Sign In or Next.
Note: The sign in screen may look different for you depending on your email provider.
If 2-step verification is enabled, verify yourself using the method you set up (6 digit code, phone call, or Microsoft Authenticator app).
Note: If you're prompted to Set up 2-step verification for Office 365, it may be required by your IT admin.
Outlook may request permission to access your calendar, contacts, etc. Tap Yes or Allow.
You're now ready to use Outlook for Android!