Hello Sandeep !

If you will get the "share URL" of WhatsApp then you may apply it via sys_menu_item table. See an example with Twitter:

INSERT INTO `sys_menu_items` (`set_name`, `module`, `name`, `title_system`, `title`, `link`, `onclick`, `target`, `icon`, `submenu_object`, `visible_for_levels`, `active`, `copyable`, `order`) VALUES

('sys_social_sharing', 'system', 'social-sharing-twitter', '_sys_menu_item_title_system_social_sharing_twitter', '_sys_menu_item_title_social_sharing_twitter', 'https://twitter.com/share?url={url_encoded}', '', '_blank', 'fab twitter', '', 2147483647, 1, 1, 3);