A post slug refers to words and dashes that describe a post in URL form. Post slugs typically use content from the post title in order to create a permalink that’s readable and relevant. It is generally used to create a valid URL for each post. Post slug in WordPress is generated automatically however, one can easily change it by clicking on the edit button present in the post. Every post has a particular slug which helps in giving it a custom permalink structure.
Once the post is published, one should avoid changing the slug of the posts as then the content of the post will get published on multiple pages and all the links pointing towards the previous page will get broken.
One should always pay extra attention to optimize the post slug correctly so that it becomes SEO friendly. The WordPress post slug should contain the target keyword of the post. While setting up the post slug, one should always remember to replace the space with dashes(-) and also ensure to use lowercase letter only.