Here's how you can set up multiple accounts on the Outlook.com app for Android.
1. Go to your inbox in the Outlook.com app.
2. Swipe to the right or tap on the tiny arrow in the upper left.
3. Tap on the arrow next to your account name.
4. Tap on the Add Account option.
5. Add your accounts.
For more, see the original article at the link below.