Lightroom has non-destructive editing. That means there is no need to keep two copies of a file (original and edited) you just have the original and the program stores the settings edits you make and when you export the picture it applies the changes to the exported file.
Want multiple versions of the file with different edits to each, make virtual copy (ies) or take what it calls a snapshot. Same deal. It also keeps the full history of every setting edit you make so at any time so you can go back and forth with your changes with ease. You can also use external editors with lightroom, in that case it will make an actual copy of the file (with LR edits already applied), add the new file to the database and that new file is then edited in the external program.
So lets take a RAW file as a starting point, we move into the develop module. (Just a demo file, not meant as an exemplar)
I jumped back to the original of this file (History on the bottom left).
Lets start off with Auto Tone to see what that does...
Not terrible, could certainly be tweaked more from here but lets see about the perspective next....
Again not bad for first shot on auto.
Lets use a preset to make the subject pop a little more (it auto masks the subject and I can change that at will)
Maybe B&W?
Notice the history in the bottom right. That is every change I have made, yet the original file is completely unchanged. LR is just showing me the results of the edit to the original file, it hasn't changed the original file at all. This is non-destructive editing.
If I want this file to share I just export it and LR creates a new file with the edits I made and it gives many file format possibilities for the export.
It can also be integrated with online photo platforms to auto sync changes you make, has full printing modules and much much more.
I mentioned that I store most of my files on a NAS (with backups). I don't even need to be connected to the NAS to see the files stored on it. Lightroom keeps a thumbnail of all the files in the database and I can still search for images and even apply preliminary editing to the file without being connected to the NAS. Obviously, I can't export without being connected but I can make adjustments and once connected again I can export with those adjustments automatically being applied.