Follow these steps to setup your Microsoft Office 365 mailbox on your Apple iOS device:
1. Go to your iPhone or iPad's Settings > scroll down and tap Apps > Mail > Mail Accounts >Add Account.
2. Select Microsoft Exchange
3. Enter your email address and a description of your account. Tap Next.
4. Tap Sign In.
If a popup asks you to choose between "Work or school account" and "Personal account" always choose "Work or school account"
5. Enter the password associated with your Office 365 mailbox. Tap Sign in or Next.
6. The Mail app may request certain permissions. Tap Accept.
7. Choose the services you want to sync with your iOS device and tap Save. You're done!
