WWDC 2014 Recap: iCloud Drive
iOS 8 and OS X Yosemite have a new feature built right in. This is called "iCloud Drive" and is like Dropbox, but by Apple. It lets you keep important files stored in iCloud. By using this service you can access those files from anywhere on a Mac, iOS device, or Windows computer. It's basically like iCloud, but lets you store more things other than iWork files.
A basic iCloud account gives you 5 GB free, but for extra you can get more space and upload more files to the cloud. You can learn more about it here.