Hi Jdillard, that block of text or HTML is generally called the "signature". Your email website or your email program should have a place where you can edit the signature.

If you are using Firefox with a webmail site and you can't find that option, do you want to mention what site you are using? Maybe a volunteer can find the site's instructions or knows how to do it.

If this problem is in the Thunderbird email program, see this article: Signatures.

Thanks, I am using Yahoo and I know I can change the address because I have done it, but I can't find out how I did it.

Jdillard said

Thanks, I am using Yahoo and I know I can change the address because I have done it, but I can't find out how I did it.

Maybe this will help :

https://help.yahoo.com/kb/SLN16030.html

And also :

https://www.lifewire.com/set-up-yahoo-email-signature-1174491