Go to the My Apple ID website (appleid.apple.com) and follow the instructions to reset your Apple ID password.
For more information, see the Apple Support article Apple ID: Changing your password.
After changing your iCloud password, make sure you update it on all your devices and in any email apps you use to get your iCloud email.
On your iPhone, iPad, or iPod touch: Go to Settings > iCloud, then tap your iCloud account.
On a Mac: Choose Apple menu > System Preferences, then click iCloud.
On a Windows computer: Open iCloud for Windows.
In your email apps: Check the help provided for the email apps you?re using.
If you set up iCloud on your iPhone, iPad, or iPod touch, make sure to set up a passcode lock on your device for added security. (Go to Settings > Passcode or Touch ID & Passcode.)