When you create a post in WordPress, it will be published with a unique URL. This URL can be used to create a link that goes directly to that specific post, sometimes called a “permalink.”
The “slug” part of the post slug is the unique suffix that is appended to the URL of your website in order to create a unique link to that post. For example, if you publish a post called “Bladerunner Review” on your website “www.MyMovieReviews.com”, then the URL of that post might look like “www.MyMovieReviews.com/bladerunner-review/”. The “slug” part is the “bladerunner-review/” at the end of that URL.
When you begin writing a post, WordPress will automatically generate a slug which you’ll see displayed just underneath the post’s title (in a section called “slug”). You can, however, edit this slug to anything you like as long as it does not contain any spaces.
If you want to change how WordPress generates post slugs, log into the administration area of your site and click on “Settings” and then “Permalinks” from the left-hand column. From there, you can customize how slugs are generated for each new post, including whether the date is included, et cetera. Keep in mind that changing the post slug settings will not affect any previously published posts (and their slugs).
Note: Not every version of WordPress contains the “Permalinks” option.
Since both internal and external links will go to the URL which includes the post slug information, it is not recommended that you change the post slug after a post is published. If you do change a post slug after publishing a post, all existing links to that post will now be “broken” and no longer work.