There are several ways to reset an account password in OS X. The primary method is to use the Users & Groups system preferences, under which you can use the "Change Password" option for your account (called "Reset Password" for other accounts), but you can also use the hidden "resetpassword" tool in the OS X Recovery drive; or if you are savvy with the Terminal, boot your system to Single-User mode and use the "passwd" or "dscl" commands to give a specified account a new password.
While all of these available options have their own conveniences, you can also associate your account with an Apple ID and use that as a means to reset your password. Of course this requires a valid ID be linked to your account, so first create and associate one to your account by following these steps:
- Open the Users & Groups system preferences
- Authenticate and then select your user account
- Click the "Set" box next to the Apple ID field
- Enter your Apple ID, or choose "Create Apple ID" to make a new one. You can associate more than one Apple ID to your account.
- Check the box for the option to "allow user to reset password using Apple ID"
Next close the Users & Groups system preferences to save these changes, and you should be all set up.
Now if you forget your user account password you can reset it directly at the login window using your Apple ID. To do this, after using the wrong password several times, the system will issue a message stating if you forgot your password, you can reset it using your Apple ID. The message will have a small arrow in it, which when clicked will initiate the password reset process. Click this arrow and follow the on-screen instructions, and your password will be reset.
As with any password change, this process will break the link to your account's default keychain, so passwords to mail accounts, Web sites, and other services that you have saved will need to be re-entered and re-saved when you access those services.