1. Access your iOS Settings.
2. Locate the Mail option.
3. Access the Accounts section.
4. Add a new account.
5. Select account type Other.
6. Select the CardDAV account type.
7. You should now see a screen asking for some information which you have to fill in:
Server: This may vary depending on which server you’re hosted on – look for the Calendars & Contacts feature inside cPanel for the exact hostname to use.
Username: Your email address.
Password: The email account password;
Description: Any description that you want
Once done, the cPanel address book will be synchronized with your iPhone address book.