On newer PCs they have integrated the one drive cloud storage so it's hard to tell it isn't only on your computer. It's actually quite useful for things you do want to share between computers and a useful backup but it will soon fill up if you let the computers constantly save and back up everything to it - so just need to be more selective about the folder path when saving things.
Or go into it periodically and move or delete what you don't need in there.15GB they give you free should be enough really with a bit of regular housekeeping.