for anyone wondering, you don't need to do backend stuff nor do you have to use a .htaccess file. change this
index.html
about.html
products.html
terms.html
to this
index.html
about/index.html
products/index.html
terms/index.html

source: https://stackoverflow.com/questions/5730092/how-to-remove-html-from-url

um u guys just trollling i found another way suckers good luck

you mean you dont want the .html ending when people visit your website?

You can see the console tab (like right next to the site display). Unlike @InvisibleOne 's answer, this will work for every single instance that you want to remove an html file.

rm [file].html
The file is the name of the file

Select the file, then click on the three little dots on top of each other at the right side of the highlighted file, and then press delete.