You don't remember the password for your Apple ID and can no longer download apps from the AppStore!
You can reset the password for your Apple ID,via the below procedure:
Go to this Link and under "Manage your Apple ID", click on "Reset your password".
Enter your Apple ID in the appropriate field (the associated email address).
Select your authentication method:
Select Email authentication and press next.
You shall receive an email with a reset link.
Click on the link and follow the on-screen instructions.
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