<!--instead off https://api.whatsapp.com or whatsapp://send-->
<a href="https://api.whatsapp.com/send?text=<?php echo urlencode($share_link);?>" onclick="window.open(this.href, 'sharer-popup-linkedin', 'menubar=no,toolbar=no,resizable=yes,scrollbars=yes,left=370,top=115,width=626,height=438'); return false;">
<!--use https://wa.me/-->
<a href="https://wa.me/?text=<?php echo urlencode($share_link);?>" onclick="window.open(this.href, 'sharer-popup-linkedin', 'menubar=no,toolbar=no,resizable=yes,scrollbars=yes,left=370,top=115,width=626,height=438'); return false;">