You can always update your password if you are logged in. You can find your password settings underneath the "Your Account" menu in the competition dashboard.
To access "Your Account" and change your password:
Click on the account icon (circled in red in the example shown)
Once in the menu, input and confirm your new password in both the "Password" and "Confirm Password" fields and save your changes.
Can't get into the app and forgot your password? Read this article: "Resetting my password"