I saw some of the wordpress plugin which on top of the rich text editor have a button and when they clicked it the shortcode is automatically inserted into the editor without actually manually insert the code. what the filter hook or action hook should i use to insert this shortcode?As this method save the user from memorising the markup for shortcode. Thanks
You could use this plugin: http://wordpress.org/plugins/wp-shortcode-helper/
This adds a dropdown in your wordpress editor.
Just create a file called 'shortcodes.json' in your template-folder and insert the info for every shortcode which should appear in the dropdown. See the example on plugin-page