email notifications

Hi sunnah,
This is not WooDiscuz issue, this comes from your WordPress default email settings. WooDiscuz calls WP default wp_mail() function it doesn’t add any changes. To configure your email “From” information please read this topic: https://wordpress.stackexchange.com/questions/9102/why-wont-wp-mail-let-me-set-the-from-header-when-plain-old-php-mail-will

mmm. not very helpful.

why not just implement this in the plugin?

Because there are thousands of other plugins, which use the same core wp_mail() function and it’s not good to affect it with 3rd party solutions. This should be configured by site admin or using an exact plugin for this purpose. There should be some, which have been developed only for changing WP mail headers, please try to search those.