First, Navigate to your Desktop Dashboard
Then, click the highlighted icon in the image below that is located in the top right of the Desktop Dashboard
Click the "Password" tab
Click the "Current password" field and enter your current password.
IMPORTANT: If you do not remember your current password, reset your password here: https://login.cardtapp.com/users/password/new
Enter your new password and confirm your new password. Then click "Update"