How to create wordpress plugin support page? [closed]

You can use the plugin_action_links_ filter for that task:

add_filter( 'plugin_action_links_' . plugin_basename(__FILE__), 'add_support_link_wpse_220726' );

function add_support_link_wpse_220726( $links ) {
   $links[] = '<a href="http://example.com/support/" target="_blank">Support</a>';
   return $links;
} 

Note that you must also pass the plugin name (plugin_basename(__FILE__)) for it to work. That’s why take into consideration from where you will call it.