Thank for contacting us.
Please note that these are different technologies and there is no easy way to convert WinForms to UWP applications. Currently, the UWP suite only contains about 20 controls and WinForms suite contains more than 100.
However, there is another solution that will allow you to add your existing applications to the store. The Microsoft Bridge allows you to convert existing applications to UWP: Desktop conversion for UWP apps - Windows app development
I hope this will be useful.
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