Step 1: Select Settings from the home screen of your iPhone.
Step 2: Scroll down and select Passwords & Accounts.
Step 3: Select Add Account.
Step 4: Select Other.
Step 5: Select Add Mail Account.
Step 6: Enter the required information below and click Next.
Name – your name (will appear as sender name)
Email – your full webmail address
Password – the password for this webmail address
Description – lets you specify any description (we suggest you use your email address)
Step 7: Select protocol type: IMAP and Settings for IMAP:
In the fields for both Incoming Mail Server and Outgoing Mail Server, indicate the following settings:
Name, Address, and Description: should have been already filled in
Hostname: mail.yourdomainname.com (or) Hostname
User Name: your email address
Password: password for your email.
Step 8: Click Save.