Frank, yes it contains a virtual printer too, for whatever that's worth! Not tried it as it's a giveaway that does nothing I need.
TK

Bruce Fraser, DocFetcher does that. It creates it's own index of your docs. And it's free. There is a paid version ($35) but that does things you will never need or use.

Ray,

Will DocFetcher index all the subfolders of a main folder.

RWW, Yes it does. And there is a Demon running in the background, it indexes any new doc put into a folder the program watches. It gives returns in a second. I have about a quarter of a million docs in my database. DocFetcher is a wonder. Use the free version, the Pro does more then you will ever need. I bought the Pro just to give the guy $35. I use both versions at the same time.

Everything search from Voidtools does that too. It's completely free and works extremely well. It's quite configurable, so you can specify which local and network drives you want it to index. I don't think it indexes cloud folders.

YossiD, Everything does NOT index "the contents of files", just indexes the locations where the files and folders are stored which is different from what the thread starter asked.
TK

Ray, I don't know the answer to this but it appears that it does make a second copy. I am currently indexing my OneDrive and it is showing messages that it is downloading the file (God only knows the destination folder).