STEP 1:

Open Outlook for Android. The icon looks like this:


Outlook for Android 


If you haven't already, you can download Outlook for Android from the Google Play Store.


STEP 2: 
Tap Get Started if it's your first time.

Or, go to Settings > Add Account > Add Email Account.


Go to Settings 

Select Add Account 


STEP 3: 
Enter your full email address, then tap Continue.


Enter your email address. 


STEP 4:
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.


Enter your password for your email account. 


STEP 5: 
If you have 2-step verification turned on, identify yourself using the method you chose (6 digit code, phone, or using the Microsoft Authenticator app.


STEP 6: 
Outlook may request permission to access your calendar, contacts, etc. Tap Yes or Allow


You're now ready to use Outlook for Android!


Source.