When users register

We can split this into two things to solve 1) remove the via part after the email address and 2) change the email.

Part 1

To get the “via webhost” part removed, you need update some records at your domain name host to prove your website host is authorised to send mail. If you don’t do this mail will probably also end up in spam. Speak to your web host or look up your hosting’s documentation about setting up (a) SPF record and also see if they support (b) DKIM

Part 2

To change the notificatiuon email From address, search for a plugin that has good reviews and is well supported, or if you are using a child theme, add the follwing snippet to your functions.php, changing the email address in bold to your chosen email. Don’t delete the quote marks.

// Change notification sender address
function change_notification_email( $wp_mail_from ) {
    return '[email protected]';
}
add_filter( 'wp_mail_from', 'change_notification_email' );