Set Up E-mail on an iPhone
The images used in this guide reflect the iOS 9.1 operating system.
Before you begin, you will need to Create an E-mail Account in Your 1&1 Package.
Scroll down and enter imap.1and1.com in the Host Name field and your full E-mail Addressin the User Name field under the Incoming Mail Server section.
Your 1&1 e-mail account is now connected to your iPhone and you can access it at anytime.