Q: How can I gift an app from the itunes store

There are instructions on how to gift content on this page : http://support.apple.com/kb/HT2736#4

If you are trying to do it from your device (iPad, iPhone, iPod Touch) and they are on iOS 6 then it won't work, you will need to try doing it from your computer's iTunes

You can also only gift content to people whose iTunes account is based in the same country as your account