How to use Tags
Tags provide a useful way to group related posts together and to quickly tell readers what a post is about. Tags also make it easier for people to find your blog. Tags are similar to, but more specific than, categories. The use of tags is completely optional.
Adding Tags via the Tags Module
You can assign and/or add new tags to posts before you publish them using the Post Tags module to the bottom right of the post editor:
You can add tags one at a time by clicking the Add button or hitting the Enter/Return key on your keyboard after typing each tag. Or you can add multiple tags at a time by separating them with a comma as you type.