The Developer .ipa file is intended to allow you to test the app on your iPad or iPhone before you send the .zip file to Apple for review. To test the .ipa file, you need to install it on your iPad/iPhone. Unfortunately, you can’t use AirDrop, Dropbox, or a similar service to install the file. Apple provides 2 ways to do this. One way is to add the .ipa file to your iTunes library on your computer, and then sync your iPad/iPhone with iTunes. But if you have a lot of content on your device, this process can be maddeningly slow. It may take 5 or 10 minutes or more to complete.
A far faster, simpler way is to use Xcode. Xcode is a free Apple development tool used to build apps for Mac and iOS. But you don’t need to know anything about Xcode or app development to use this tool to quickly and easily install an .ipa file on your iPad or iPhone. Here’s how to do it with Xcode 6.1.1
1. Download and install Xcode.
2. Run Xcode. You’ll find it in your Applications folder.
3. Wire your iPad or iPhone to your Mac with a USB cable.
4. In Xcode, choose Window > Devices, or press command-shift-2. You should see your device displayed in the Devices window.
5. Either drag your .ipa file into the “Installed Apps” section, or click on the plus sign and select your .ipa file. This will install the development app on your device. There is a bug that sometimes causes the error message below to appear. If you get this message, and you have the correct device attached, just click the OK button and try again. It should work the second time.