It’s really easy to edit your email password – all you need to do is login via the email webmail app: https://mail.ionos.co.uk/ (1and1 is now IONOS) and then click on the menu bar top right (looks like 3 lines – see below:
Then choose from the pop up menu “Edit Settings” then choose “Change Password” – see image below:
and use this secure password generator to make a good strong password: https://passwordsgenerator.net/