If you have an Office 365 work or school account, use these instructions to set up your email with your iOS device.
Set up Office 365 email in the iOS Mail app
Go to Settings, scroll down to Mail, Contacts, Calendars, and then tap Add Account.
Enter your email address, your password, and a description of your account. Your email address should be your Office 365 business account or school account such as email@example.com, firstname.lastname@example.org, email@example.com. Once your credentials have been entered, tap Next.
If you're prompted to enter additional server settings, see POP and IMAP settings for Outlook Office 365 for business.
NOTE: If using IMAP or POP to sync your email account, only your email will sync. Calendar and contacts will not.
Choose the apps you want your email account to sync with your iOS device and then tap Save. Your email account is now ready for use with the iOS Mail app.
NOTE: If you're prompted to create a passcode, tap Continue and type a numeric passcode. If you're prompted and don’t set up a passcode, you can’t view this account on your device. But you can set up a passcode later in your settings.