Deleting templates that are no needed

no need to add any code for that
if u dont what that field then comment that feild.

Deleting templates (or any other files) is not a good idea — it could mess up things with your site even if they are “not being used” or are not visible on the page.

You can safely delete author.php and category.php. Per the Template Hierarchy, both of these template files fall back to archive.php, which falls back to index.php.

However, if the site does, or could ever, use comments, then you must retain comments.php, which in turn must be called via the comments_template() template tag.