Select ‘Apple > About This Mac’ from your Mac’s menu bar.You get 5GB of iCloud storage for free, although if you exhaust this limit then you’ll need to purchase an iCloud storage plan. Note that these files will still exist in your iCloud account, so you can re-download them at any point. If you’re ever running low on memory, then macOS will free up some space by deleting the local copies of your most rarely-accessed files, within the Desktop and Documents folders. MacOS Sierra introduced an Optimize Storage feature that lets you sync your Desktop and Documents folders with your iCloud account.
