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If you use Pages, Numbers or Keynote on an iOS device, you can tell it to store your documents in iCloud. Those documents are accessible on a Mac running Yosemite by clicking on iCloud Drive in the sidebar of a Finder window (you might need to sign in to iCloud in System Preferences first). Lots of other iOS apps use iCloud this way, and their files are accessible on your Mac, too.

Dropbox is also great for sharing files between the two operating systems, and Evernote automatically syncs your notes between devices.