I have installed magento 2.3.6 under https://www.cheapglasses123.com
How to remove .html from category and product url?
Admin Path: Stores->Configuration->Catalog click on Search Engine Optimization tab
Here you can remove below-mentioned fields:
Product URL Suffix
Category URL Suffix
Make these fields blank (remove .html from both fields) save the config and reindex and clear cache of your store.