Write an article based on this summary:

Contact your IT department. Open the Settings app on your iPhone. Select "Mail, Contacts, Calendars." Tap "Add Account" and select "Exchange." Enter your full email address and password. Ensure that "Mail" is toggled on and tap "Save." Create a passcode if prompted.
Many companies do not permit workers to access email from outside of the workplace for security purposes. Check with your IT department to see if you can even access your email at home. They can often provide you the best instructions for getting connected as well. If you have an Office 365 for Business or Exchange-based email account, you may be able to add it to your iPhone's Mail app, provided your IT department has allowed outside connections. This will open the settings for all of your connected email accounts. This will allow you to add Exchange and Office 365 for Business email accounts. Make sure to include the domain at the end of your email address (e.g. "name@interslice.com"). This will add your Exchange or Office 365 for Business account to your Mail app. If you cannot connect to your Exchange or Office 365 for Business server, contact your IT department, as they may not allow connections from mobile devices. Some Exchange servers will require you to create a passcode when adding your account. You'll be prompted for this passcode when checking your work mail.