You need to download the Philips HealthSuite health app for every device you wish to access your account on.
For Android go to the Google Play store, for iOS go to the Apple store and look for the 'Philips HealthSuite health app'. Then download and install the app.
Please note that you will need to re-pair your Philips connected health devices to the new phone. The app will prompt you to do this once you logged in from the new phone.