These are the required settings for receiving your emails on other devices like the iPhone, iPad etc

Basic Details
Name : Your name
Email : Your full email address
Description : Free text  

Incoming Mail Server
Host Name : pop.ionos.co.uk
Username : Your full email address
Password : Your password (originally set up by your support team)

Outgoing Mail Server
Host Name : smtp.ionos.co.uk
User Name : Your full email address
Password : Your password (originally set up by your support team)

For further information check out the links below

OUTLOOK
https://www.ionos.co.uk/help/email/microsoftr-outlook/manually-set-up-an-email-account-in-microsoft-outlook-2016-imap-or-pop3/

APPLE MAIL
https://www.ionos.co.uk/help/email/other-email-programs/setting-up-an-email-account-in-apple-mail/ 

IPHONE
https://www.ionos.co.uk/help/email/using-11-ionos-email-accounts-on-apple-iphonesipads/add-a-mail-basic-email-account-to-your-iphoneipad/

ANDROID
https://www.ionos.co.uk/help/email/using-11-ionos-email-accounts-on-android-smartphones/setting-up-an-email-account-on-an-android-smartphone/