private key certificate

On May 17th 2021 I electronically signed a document - I think it may have been an Adobe form.

Apparently, as part of that process I created a “private key”.

Now when I create an email before i can send i have to first enter the password for the login keychain, then enter the same password again in a second dialog box to “sign using the key privateKey”.

If I choose “deny” in either dialog box the email will not be sent.

How do I stop this process?

I have deleted the certificate from the login keychain, shut down and restarted the MacBook, but it keeps reappearing and must be deleted again. I presume the "certificate" in my login keychain is the "private Key" because it was created on the date and time I signed the form.

How do I delete the certificate permanently ?

Here’s what i delete and it keeps reappearing. 

Here’s the two dialog boxes that appear when I attempt to send email.

Thanks,

G. Morton