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It seems that you are misunderstanding the Microsoft Store. First of all, the Microsoft Store app is the user interface of Microsoft Store. It is the same Microsoft Store that you are accessing no matter you are using Windows 10 or Windows 11. The new Microsoft Store supports both Windows 10 and Windows 11. When you upload your app to the Microsoft Store, your app should be available for both Windows 10 and Windows 11 unless your app only supports OS versions lower than Windows 11.
If you want to upload your app to the store, you must follow the Store policy. The new Microsoft Store makes it easy to upload your app but you still have to make sure your app follows the store policy to pass the certification.
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