Categories are used to put related posts together in one group, under a common link.
Example: While running a Network Marketing blog, you could have categories according to the nature of the products. Health and Beauty, Fitness, Household Items, Books and so on.
Tags are a subset of categories. They are useful when you want to break down categories into smaller, more accurate descriptions.
Example: Under each product category, you could have tags that specify the function of the product. For example under the Health and Beauty category you could have tags like make up, personal hygiene, supplements, nutrition and so on.
This will enable you to sort your website content into groups of closely related topics, thus making it easier for your readers to find what they are looking for. Post categories can even be added to the main navigation of your blog to further aid your readers in finding your best content.
How to create tags and categories:
As a rule, every new post created on a WordPress blog must fall under at least one category, the default one being “uncategorized.”
You must create your own categories then, so as to better reflect the theme of your blog. While writing a new post, you will see a table like this on the right hand side.
Simply input your preferred category and tag names in the “add new” sections and when you publish your post, they will be saved automatically for future reference.
This is how tags and categories appear to a reader,at the bottom of each post.
Each one is a link and when the reader clicks on it, he/she will be taken to a section containing only those posts filed under the chosen tag or category.
To delete a category, go to dashboard – posts – categories and you’ll see a red “delete” link below each category name. Click on that to delete the category.
To delete a tag, go to dashboard – posts – tags and you’ll see the delete link there too.