Here is a snippet to output the current categories of a post in the Post Archive or on your single Post:-
<?php $categories = get_the_category(); $separator = ', '; $output = ''; if($categories){ foreach($categories as $category) { $output .= '<a href="'.get_category_link( $category->term_id ).'" title="' . esc_attr( sprintf( __( "View all posts in %s" ), $category->name ) ) . '">'.$category->cat_name.'</a>'.$separator; } echo trim($output, $separator); } ?>
This displays the posts with a link to the category archive delimited by a comma – edit line 3 to update the separator which is trimmed off on the last category,