There are two ways to change your password on MV. If you are unable to login and you forgot your password, you can click "I Forgot Password" at the login screen to send a password reset email to the email attached to your account.
To change your password while logged in, go to your drop-down menu > My MV > Setting > Security Center and click 'View' next to "Change Password". Enter your current password, then your new password twice. Click save and you will be logged out of your account and you can now login again using the new password.
When creating a password for your account we recommend using a strong password that contains at least 1 uppercase letter, 1 lowercase letter, a number and a special character.