Your Apple ID is tagged to a country/region and you can purchase or download an app only if it's available in that country/region. In most cases, apps are available for all countries and this shouldn't matter much but infrequently, you might stumble on an app which is available for only some countries. In these cases, you won't be able to download/install the app.
The quickest workaround for this is to change your app store country/region. Thankfully you can do this right on your iPhone/iPad by following some quick steps that we've mentioned here. Check it out.
How to Change App Store Country on your iPhone/iPad on iOS 8
- Open the Settings app
- Tap on iTunes & App Store
- Tap on your Apple ID
- Then, tap on View Apple ID
- Enter your password and you will get to the account information
- Next, tap on Country/Region
- Tap on Change Country/Region
- Select a country that you want to change to (for example, U.S.A)
- Tap on Agree when you are shown the terms and conditions
- On the next screen, you have to make sure you add a valid zip code and a credit card that's valid for the country you've selected. If you can see a None option for payments, select that.
- Then, tap on Next
- Once you're done, you will see a message that says your Apple ID is now ready to shop on the specific country you selected. Tap on Start shopping and you're done.
The trick part of this is when you have a credit card associated to your Apple ID. If you have no credit cards selected or added, the None option is readily available and you can breeze through the process without a problem. But if you have added a credit card and the None option doesn't show up, you will need to add a valid credit card whose address matches the country you have selected.
Video Tutorial on Changing App Store Country Region in iOS 8 on Your iPhone or iPad