How to Add BCC to Email Notifications (for all forms)

add_filter( 'wp_mail', function ( $args ) {

    // Add the BCC email address here

    $bcc_address = 'Bcc: [email protected]';

    if ( ! empty( $args[ 'headers' ] ) ) {

        if ( ! is_array( $args[ 'headers' ] ) ) {

            $args[ 'headers' ] = array_filter( explode( "\n", str_replace( "\r\n", "\n", $args[ 'headers' ] ) ) );

        }

    } else {

        $args[ 'headers' ] = [];

    }

    $args[ 'headers' ][] = $bcc_address;

    return $args;

});