making proper pages’ link

I would like to know how I could make the pages appear like this format:

https://urlofsite.com/webmistress/collections/

instead of :

https://urlofsite.com/webmistress/?page_id=2

sample blog site would be:

https://www.voguecrown.net/site

anyone could tell me how did she made it that way? since I think it’s much more presentable plus it’s easier to put up the links.

I am confuse about it since whenever I put new pages it all
appears on my sidebar control panel. I don’t want it that way.

thanks in advance