RSS feeds are automatically generated by WordPress to allow readers to easily follow your blog using an RSS feed reader.
You can find the RSS feed for all posts on a WordPress site by going to
http://example.com/ is the home page of your WordPress installation.
The feed for all comments can be found at
http://example.com/ is the same as above.
The feed for all comments on a particular post can be found at
http://example.com/post-slug/ is the permalink of that post.
You can read more about RSS feeds and other types of feeds generated by WordPress at the WordPress Codex.