Most of the emails that originate from a Community Server site use the admin users email address in the From address.
This means that when a user joins your site, the welcome email will appear as though it is from the admin user’s email account. However, you may want to have these emails appear as though they are from a different address. For example, for new user accounts you could have the email sent appear as though it is from accounts@yoursite.com.
Procedure
<fromAddress>[adminemail]</fromAddress>
to
<fromAddress>accounts@yoursite.com</fromAddress>
The next time a user joins your site they will receive an email from accounts@yoursite.com. You can also change the fromName, which may have the value of Yoursite Accounts. You can follow these same basic steps to change any other type of email templates from address.