How to switch on Vietnam app store to japan app store

However, you must be a legal resident of Japan, provide a Japanese payment method and have a verifiable Japanese billing address to use the App Store for Japan.

You can't just randomly switch to another country's App Store because you want apps from that store.

M1 Mac mini, macOS 11.2.3; Watch, series 5 GPS/cellular, watchOS 7.3.3; iPad Pro 2nd Gen, iPadOS 14.4.2; iPad Air 2, iPadOS 14.4.2; iPhone 12 Pro, iOS 14.4.2; TV 4th Gen, tvOS 14.3  HomePods, audioOS 14.3 and Airport Express w/ Airplay 2

Hey cirtelbobo,

It sounds like you're looking to change the region for the App Store. We can understand wanting to get that resolved. We want to help.

We'd recommend the steps in this article: Change your Apple ID country or region

Thanks!