add an input field to add/edit post form in wordpress

I’m making a WordPress plugin,while I was developing I altered posts table for adding new column using $wpdb->query()

now I need to add an extra input field in “add new post form” and “edit post form” in adminarea and save that extra input field value to database

anyone has any Idea how to do this ? I think I should filter it but I can’t figure out how.

I searched a lot but no luck

Thanks