Email received by users may have WordPress [wordpress@”yoursite.com”] in the line From:
To change this, edit the following.
…wp-includes/pluggable.php (around lines 375 and 391).
Change these lines:
$from_name = 'WordPress';
$from_email = 'wordpress@' . $sitename;
$from_name = 'Name or your website';
$from_email = 'admin@ or whatever@' . $sitename;
Same to the same location.