In order to keep your Mac computer secure, it’s best practice to set a password which must be difficult to guess for others. Especially, if you are an administrator, which has the highest privileges on your Mac computer. Here are step to accomplish the password change on a Mac:
Step 1: Click on the Apple logo and then click on System Preference:
Step 2: Click Accounts under System
Step 3: Click on the User and then click on Change Password
Step 4: Enter Old Password, type New Password and retype to Verify. You can also write some Password Hint to use it in future to recover forgotten password and then click Change Password
The User password is now changed.
Note: Admin also has the privileges to set passwords for other created accounts on the Mac computer.