removing 'recent' files names from finder in MacOS
I'm assuming you are talking about Finder > Go > Recents

Files there cannot be deleted without deleting the files themselves. It's just an alternate view of the files on your computer. 

(If you are instead talking about the Apple Menu > Recent Items or Finder > Go > Recent Folders, those both have a "Clear Menu" option at the bottom of the menu)

see:
https://discussions.apple.com/thread/8137012