iCloud: Change your iCloud account password
Your iCloud account password protects the privacy of the information (such as your email) stored in iCloud. Your password also protects your ability to locate or remotely erase your device using Find My iPhone. You should regularly change your iCloud password to protect your information.
Change your iCloud account (Apple ID) password
Go to the My Apple ID website (appleid.apple.com) and follow the instructions to change your Apple ID password.
Here are some tips for creating a secure password:
Make your password long (at least eight characters). A password can be up to 32 characters long.
Make sure your password uses a combination of numbers, letters, symbols (for example, @, $, or %), or letter cases (passwords are case-sensitive).
Don’t use words found in the dictionary, number sequences (“1234”), or keyboard patterns (“qwerty”).
Don’t use the same password for multiple websites. For example, create unique passwords for iCloud, your banking website, online stores, and so on.
Turn a memorable phrase into an acronym. For example, the phrase “In 1990, I was married in the city of Los Angeles,” could be used to create the password “I1990,!WmitcoLA.” Mixing the case and including symbols makes the password stronger. Of course, don’t use this password example; customize a phrase of your own.
Never write down your password or tell it to anyone.