nyodulf on "[Plugin: WP Mail SMTP] Contact Form 7 correct reply to address workaround"

Another option is to add this to a child-theme or plugin functions.php file:

function addSmtpReplyTo($phpmailer)
{
    $phpmailer->addReplyTo($phpmailer->From, $phpmailer->FromName);
    return $phpmailer;
}
add_filter('wp_mail_smtp_custom_options', 'addSmtpReplyTo');

That will automatically add the "From" email address and name as the Reply-To email and name - useful if you have a lot of contact forms.