iCloud a name many still don’t know how to use effectively since it debuted in 2011 in Apple’s Developers conference. Since its my first posts since i stopped I’ve decided to make things easy on many out there giving a really simple explaination on iCloud. iCloud is not an app or service by its own but rather an application suite its main use is to sync all of your iOS devices and Mac ( Photos, Mail, Contacts, Calendar, Reminders, Safari, Notes, Keychain ( saved Passwords) ) wirelessly though apple servers. For example No matter where you add a new Note you will find it on all of your iOS & Mac which have the same iCloud account which is basically your apple account.
Now how to setup iCloud on your devices, first if you own a Mac go to System Preferences, iCloud and insert your account and simply check the things you wanna sync through iCloud.
Now go to you iOS device (iPhone, iPad) into settings, iCloud and again do the same thing toggle the switch of the application data you wanna sync though all your apple devices.
Keep in mind that for each iCloud account you only get 5 GB on sync data no matter how many apple devices you own its 5GB if you need more storage especially for your photos i would recommend you upgrade.