Thanks for your suggestions but the BP default theme that i’m using there isnt any file named footer.php. in buddypress bp-themes –> bp_default there is a folders named _inc which further has folders css and images.
That’s because “default” is a child theme. It inherits it’s footer from it’s parent theme. To create a custom footer for you child theme… just copy the footer.php file from the parent into the child. The child footer will override the parent.