How to Change the Password for an Apple Mac Laptop
From the moment you create an account on your Apple laptop, you must also create a password for your account. If you are the first user on the laptop, your username and password is by default the system administrator. This system administrator username and password is used to log in to your account, access specific areas of your laptop and must be entered when adding or removing applications. To protect your privacy, change your laptop password periodically.
Click the "System Preferences" icon on your screen's dock, or click the "Apple" icon at the top of the screen and select "System Preferences" from the drop-down menu.
Click the "Accounts" icon, and click your account name under the "Accounts" section in the program window's sidebar.
Click the lock icon in the lower-left corner of the screen to unlock the Preferences, and enter your system administrator name and password. Click "OK."
Click the "Password" tab, and click the "Change Password" button next to your account picture. Type in the previous password in the "Old Password" field, and create a new password in the "New Password" field. Type in the new password again in the "Verify" section, and enter a hint that only you will remember in the "Password hint" section.
Click the "Change Password" button to save the changes. Click the lock icon in the lower-left corner to re-lock the Preferences to prevent any further changes.