From your iPhone, go to Settings and scroll down until you see Passwords & Account.
Tap one time on Passwords & Accounts and Add Account on the next page.
Select Microsoft Exchange, then enter your email address and a description – by default it will copy your email address, tap on next
Select the option Configure Manually.
You will need to first enter your password and you will see new fields. Replace Server and Domain by the information given by your IT technician.
You will be then redirected to a new page to select the options to synchronize. Tap on next and you are all set.