A SEO friendly URL accurately describes the page using keywords that are easy to read for both search engines and users.
This is an example of an SEO friendly URL:
https://www.templatetrend.com/blog/post/how-to-enable-debug-mode-in-prestashop-1.7/
Unfriendly URLs consist of a mix of numbers and words giving a shopper any information about the destination of the link.
This is an example of a NON-SEO friendly URL:
https://www.templatetrend.com/folder/x1234562/12
You can also enable redirecting to canonical URLs – these are original URLs, so in case your site contains duplicated URLs, a user will be redirected to the original one. In order to find the settings.
PrestaShop admin panel go to Preferences => SEO & Urls >> Enable Prestahsop Friendly URL.