vim is the improved version of vi (short for visual editor) which is an old school text editor for UNIX based operating systems (Linux, BSD, OSX etc). Once you download vim, and note, this is not simply point and click editor, there is a learning curve.
There is a lot of documentation to get started. Give yourself about 10 hours just to get used to navigating the editor to edit traditional documents, there's that much of a learning curve. You might find it easier to learn by playing the vim adventure game or the less pretty but arguably more useful, try out vim genius until you can pass level 4.
If you decide to stick with it, you may want to print out a cheat sheet.
I've been using it for 20 years(!), and still don't use 1/2 the features. However even with that, I can navigate a text file faster than all these newbies with their supposedly easy notepad and Word docs. If you really want a powerful, graphical editor, check out sublime text or visual studio code.
And once you've fully mastered vim, you should give emacs a try. Just kidding, no rational human should use emacs. If you're not aware, the term "editor wars" is famously coined due to the religion of which editor you prefer, vi or emacs.