Install the Outlook for Android app from the Google Play Store and then open it.
Tap Get Started if this is your first time.
Otherwise, to add another email account, open the Menu 
> Settings 
> Add Account > Add Email Account. Then skip to step 4 under Set up another email account below.
Enter your full email address, then tap Continue.
Note: If you’re asked to choose your provider, you’ll have to Set up your Exchange manually or set up an IMAP or POP 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 multi-factor authentication is enabled, verify your identity.
For more information, see Security info overview.
Enter email address. Tap Continue. When asked to select an email provider, choose IMAP.
If you want to use POP to access your email in Outlook.com, you’ll first need to enable POP access.
Select Settings > View all Outlook settings > Mail > Sync email.
Under POP and IMAP, select Yes under Let devices and apps use POP.
Select Save.