Go to iforgot.apple.com
Enter your Apple ID email address
Follow the on-screen steps to verify your identity
Choose a trusted device, trusted phone number, or email verification method
Enter the verification code sent by Apple
Create a new password
Sign in again with your new iCloud password on all your devices
If you cannot access your trusted device or phone number, use account recovery at iforgot.apple.com
If needed, contact Apple Support for further help