Adding mailto link on the WebSite description

Good afternoon
I have tried everything to get a mailto link on the description of the website and frankly I have failed to do so. I tried function.php, I tried style.css, I have tried editing Header.php and frankly nothing seems to work, it is very frustrating but an understandable issue.

Well, thank you very much for your attention, and I hope to solve this A.S.A.P. (need to launch the site on Monday)