How can i change this URL  

https://fearless-assassins.com/articles.html/members-wiki/

to https://fearless-assassins.com/members-wiki/ 

Can someone please help? 

 

"articles.html" is the URL of the page. It’s required, but you might change or shorten it. The “.html" is optional. 
"members-wiki" is the name of a Pages database category. That’s also required, but you could run a database without categories. 
So if you would delete the database categories and rename the page to “members-wiki”, you would get the URL you want.