I uploaded my app on iTunes. My app is universal, for iPad and iPhone. On iPhone test-flight it is showing but on iPad test-flight it is not showing. What is the reason?
If you are using the same Apple ID on that device - you should re-add account to testers in iTunes Connect, then open e-mail with link to the application on that iPad and open the link.
If you are using another Apple ID - just add it to testers in iTunes Connect and proceed as above.