iCloud: Sign in to or out of icloud.com
To use iCloud web applications, you need to sign in to icloud.com on a computer.
To prevent anyone from accessing your iCloud information at icloud.com (such as your email) while you’re away from your computer, you can sign out of your account.
Sign in to icloud.com
Go to icloud.com, and sign in using your Apple ID (the one you use with iCloud).
If you select the “Keep me signed in” checkbox, then anytime you return to icloud.com within two weeks you are not asked to sign in (except to use Find My iPhone, which continues to require your password). You stay signed in to icloud.com even if you refresh your browser window, close the browser window where you are logged into iCloud, or quit the browser application.
If you have trouble signing in, check these troubleshooting tips.
Sign out of icloud.com
From any iCloud web application, click the iCloud button .
Click Sign Out in the upper-right corner.
If you didn’t select the “Keep me signed in” checkbox when you signed in to icloud.com, you can also sign out by quitting your browser application.