For Windows phone - currently build.phonegap.com does not support WP8 QR code installation. You need to download WP8 sdk, and then you can use Application deployment tool to install your apps on a WP8 device or Emulator.
iOs - 1. you need a developer account for iOs 2. you need to create provisioning profile with UDIDs of iOs device registered for development. 3. then you need to convert your iOs developer certificate to .p12 and upload it alongside with provisioning profile to build.phonegap.com
I hope that helps.