URL rewrite allows you to use shorter and a bit more SEO and user-friendly URLs.
Here is an example of article URL without URL rewriting:
Here is the URL to the same article with URL rewriting:
Check the URL Rewriting setting at Customization > Styling and Front-end Settings:
It detects status of URL Rewriting components during installation, and if they are working, URL Rewriting will be turned on automatically. In this case you do not need to do anything.
If URL Rewriting is turned off and you want to enable it, follow the guide that matches your server configuration:
Then you can enable rewriting of URLs at Customization > Styling and Front-end Settings: