Log into your account with your email address and password, then navigate to the top right corner of your screen, click on your headshot, and select Edit Account Details from the dropdown menu.
Here, select 'Yes' where it asks Would you like to change your password? and enter in your new password. Your password must be at least eight characters and contain one uppercase letter, one lowercase letter, and one digit.
Be sure to click the Save Account Details button at the bottom of the page to save the password change.
Have you forgotten your password? Read this article on how to reset it.