Add custom directory in URL

How can i add custom “directory” in my URL for pages and posts?

So the main website url is: http://www.example.com, but when i go to a page I want this kind of URL: http://www.example.com/SOMETHING/new_page

How can I put that “SOMETHING” in URL without affecting WordPress functions?

Go to your

Dashboard => Settings => Permalinks

click on Custom Structure and paste this /something/%postname%/

And you can replace something

It will add the something keyword before pages and post url slugs.