Finder

From ICHKWiki

Finder is a searcher which is useful if you want to find something that you couldn't find in the computer, all you have to do is just type in the application/document name in the search bar and the finder will go over the whole computer and give you what you want. It is actually a true "Finder".

Finder also controls your desktop, and helps you arrange files so that it can be easily found. It is a really useful thing

Finder is the core of the Mac OS os if you manage to quit it your computer will not function properly.