Hii..........Can anyone tell me is there anyway to change footer in every post or page i want to include some different content in every pages or posts
To do this you must edit your footer.php. You can use the is_single() and is_page() function. See this documentations for more info. http://codex.wordpress.org/Function_Reference/is_page http://codex.wordpress.org/Conditional_Tags#A_Single_Post_Page
all you have to do is go to your theme folder, you will find footer.php . make changes to it and it will be reflected on whole site. You just need to do it once.
it sounds like youre talking about editing the post content... if thats the case you would make edits in the bottom of singlepost.php NOT footer.php