iCloud Keychain can also keep the accounts you use in Mail, Contacts, Calendar, and Messages up to date across all of your Macs. If you're signed in to Facebook, Twitter, Linked In, or any other accounts in Internet Accounts on OS X Mavericks, iCloud can push those accounts to your Macs as well.
Make sure you have installed iOS 7.0.3 on your iPhone, iPad, or iPod touch.
Select Settings from the SpringBoard.
Choose iCloud from the Settings menu.
Choose Keychain from the iCloud menu.
Tap to switch iCloud Keychain ON.
You will be asked to use your iPhone's Passcode as an iCloud Security Code or create a different code. We opted to Create Different Code.
You'll be asked to create an iCloud Security Code. Enter a four-digit numeric security code.
Re-enter your security code.
Enter a phone number that can receive SMS messages. This can be your own number or the number of someone you trust. This number will be used to verify your identity when using your iCloud Security Code.
Select your country and enter your phone number then tap Next.
iCloud Keychain setup is now complete.
To use iCloud Keychain, launch Safari and navigate to site where you need to login. For example, http://www.iclarified.com/login.php. Once you've entered and submitted your credentials, Safari will prompt you to save the information in iCloud Keychain for AutoFill on all your devices. Tap the Save Password button. This information will now be available across your devices.