Add Custom Share Button

/** Add Custom Share Button */
function custom_share_main_button( $main_button, $post_id ) {
    $newsletter = '<a href="https://google.com" rel="nofollow" class="jeg_btn-newsletter expanded"><i class="custom_icon"></i><span>Newsletter</span></a>';
    $subscribe  = '<a href="https://facebook.com.com" rel="nofollow" class="jeg_btn-facebook"><i class="fa fa-twitter"></i><span>Subscribe</span></a>';

    $main_button .= $newsletter . $subscribe;

    return $main_button;
}
add_filter( 'jnews_single_share_main_button', 'custom_share_main_button', 99, 2 );