Creating the Product URL Rewrite means you can change the product link for better SEO and make your site more friendly with the visitors. However, during the rewrite process, you should know what Target Path and Request Path are.
Marketing > SEO & Search > URL Rewrites.
Add URL Rewritesbutton.
Create URL Rewrites, choose “For Product” option.
Skip Category Selectionbutton, then navigate to the
URL Rewrite Informationsection.
Here, the current product URL is included by the
Request Path and the
Target Path shows the internal URL that is used by the system. It is grayed out and not available for editting.
Storeto apply the rewrites if necessary.
Request Pathfield, insert the new URL key and suffix for the product.
Redirectto Temporary (302) or Permanent (301).
And now, you can see the new product rewrite at the top of the list.
System > Tools > Index Management.
Catalog URL Rewritescheckbox.
Submitto update the index.
Be careful to check the rewrite to ensure that it works perfectly.
Ref: Magento 2 User Guide
It comes to the end of tutorial: How to Create Product URL Rewrites in Magento 2.