One, I would suggest you remove or obfuscate yore email address in a publicly available forum, unless you are partial to spam.

You can’t change your email in the forum profile as that is set in your my.avast.com account. So you will have to login to your my.avast.com account and Manage emails and either add a new email address (the correct one) or correct the incorrect email address. If creating a new email address, after validation you then set that as the default email address.

Avast would only get that email address from what you entered when you registered your avast installation.