Step 1 - On your iPhone, find and open the Settings app, then scroll down a ways and tap on Passwords & Accounts
Step 2 - Now, tap on Add Account
Step 3 - Then, tap on Microsoft Exchange
Step 4 - Type in your normal email and password and change or leave the description field. That is a personal preference.
Step 5 - It was ask you to sign in, or configure manually, tap sign in
Step 6 - Type your normal account password and tap sign in
Step 7 - Make sure all options are enabled and marked green, then tap save. Then, head to the mail app and make sure your email is coming through.