If you know the answers to your security questions
Go to My Apple ID (appleid.apple.com).
Click "Manage your Apple ID", then click "Forgot your password?".
Enter your Apple ID and click Next.
Select "Answer security questions" as your authentication method. Click Next.
Select the birth date associated with your Apple ID, then click Next to begin answering your security questions.
After answering your security questions, you will be asked to enter and confirm your new password. Click Reset Password when done.
If you have access to the email address associated with your Apple ID
Go to My Apple ID (appleid.apple.com).
Click "Manage your Apple ID", then click "Forgot your password?".
Enter your Apple ID and click Next.
Select "Email authentication" as your authentication method. Click Next.
Apple will send a message to the email address associated with your Apple ID. Open the message and click "Reset Apple ID password".
When the My Apple ID page opens, enter and confirm your new password, then click Reset Password.
If you have two-step verification turned on
Go to My Apple ID (appleid.apple.com).
Click "Manage your Apple ID", then click "Forgot your password?".
Enter your Apple ID and click Next.
Verify your identity by entering the Recovery Key you were provided when setting up two-step verification.
A verification code will be sent to the trusted device associated with your Apple ID. Enter the verification code.
Enter and confirm your new password, then click Reset Password.
If you don't have your Recovery Key or are unable to receive messages at your trusted device, follow the instructions for what to do if you can't sign in with two-step verification.
Additional Information
Refer to the Apple ID Support page if are unable to reset your password using the steps in this article.
If you know your Apple ID password, you can choose to change your Apple ID or change your password.