When you add a new domain to your account, the system may also enable DKIM in outgoing mail and also add a DNS record into that domain's DNS for the DKIM feature.

The purpose of the DKIM feature is to allow outgoing mail from you to be automatically digitally signed in such a manner that recipients can verify with a high degree of confidence that the mail really originated from the server that you usually use. If any third party sends mail with headers forged to make it look like the sender is in your domain, recipients will notice that the email contains no digital signature, and they may choose to treat the email like spam.

if your control panel shows that DKIM is not active, you may go into the email settings and activate it.

If you want to disable DKIM, first disable it in email settings, and then you can remove it from your DNS.

If DKIM is enabled in email settings but removed from DNS, mail that you send may fail authentication. Receiving sites may reject it outright or, if they accept it at all, send it to the recipient's spam folder.