Are you conversant with the difference between files stored online versus locally, and that you're looking for data files in the right place and if locally, in the right folder?

Unless you're a power user dealing with files with a lot of advanced and macro-driven embedded features, you should be quite happy using free LibreOffice. Or even free Google Docs, which is a bit more simplified but offers features most average-level users need.

I think your first paragraph nails it; that's my problem. Of course, OneDrive is online and I'm trying to access the same OneDrive on my account from two different computers, to use as a file transfer facility. My question is "How do I make sure I logging on to the same one?

Regarding your second paragraph, I find the various Office clones in adequate, especially Google Docs. It's not that I'm a power user, but the details are different enough that it's worth the annual price of a subscription. Of course, I would have preferred to buy a DVD with the software and license on it, but MS doesn't do that any more.

If you saved the file online, you should be able to access it from a different PC. I think. The easiest way to move locally saved files from one PC to another is with a thumb drive if you haven;t indicated the folder to be Shared on your network. Remember to dismount any removeable storage media, whether a thumb drive, an SD card, or an external drive, before disconnecting it from a PC.

With all programs and apps, it's important to be able to find folders where files are saved. Personally, I find the default folders most apps use to be very hard to access, too often buried several levels down paths with arcane names. I make it easier by creating my own folders at a high level - like a folder named Word Processing docs and then making it C:/Word Processing Docs so that it's easy to find. By using it once, that resets where the particular program/app will look for files in the future.