Step 1 » From the Settings app, select Mail, Contacts, Calendars
Step 2 » Select "Add Account"
Step 3 » From the list of available account types, choose "Other"
Step 4 » Select "Add Mail Account" to proceed.
Step 5 » Enter your name, email address and password. Tap "Next" to proceed.
Step 6 » Make sure IMAP is selected and confirm your name and email address. Swipe down to continue.
Step 7 » Enter the incoming mail server settings (substitute username and password for your own). Swipe down to continue.
Step 8 » Enter the outgoing mail server settings (substitute username and password for your own). Tap "Next" to verify your account.
Step 9 » Once your account settings have been verified, tap "Save" in the upper right of your screen.
Step 10 » Select your new account from the Mail, Contacts, Calendars screen.
Step 11 » Select your email account listed under the IMAP heading
Step 12 » Swipe to the bottom of the account settings and select "Advanced"
Step 13 » Swipe to the bottom of the Advanced settings screen and change prefix to INBOX (all caps), then click Account to return to previous screen. Tap "Done" to save changes.