By default, your blog posts url structure will be the date followed by the title of the post. For SEO reasons it’s considered better to use descriptive categories in the url.
If you’re blog is setup and running then changing your permalink structure could cause problems with search engine indexing and 404s so you’ll need to go through a more complicated process to avoid losing your position in search engines.
In your wordpress admin dashboard choose the Settings menu option and click on Permalinks.
In the permalinks editor choose the Custom Structure option, delete the example in the text box then click the category button then the postname button (or any of the other buttons that you want in your url) which will auto populate the text box.
Click Save Changes.
Go back to your blogs homepage, refresh it and click on a post. You’ll see your updated url structure in the address bar.