It is very easy to configure 1&1 email settings for android if you have the right guidance. You have nothing to worry about as we are here to help you out with some simple steps. Firstly, make sure that you have an existing account and you can refer to these steps now:

Unlock your android mobile and navigate to settings
Search for the Accounts section and touch it
Choose the ‘Add account’ option on the list
If you wish to configure 1&1 IMAP settings then click on tab Personal (IMAP)
Enter your account credentials that include the email address and password in the specific tab
Enter your email and click on ‘Next’ and then enter your password
Enter the 1&1 email settings in the next tab and enter imap.ionos.com in the Server field and Select ‘next’
Enter the 1&1 SMTP settings i.e. smtp.ionos.com on the outgoing server settings page
Select ‘Next’ and then allow your preferred settings from the given options
Now you will be given the option to change your account name and the name shown to your receivers. You can do it as per your preference