Within your Visual Studio solution, right click your project, click "Manage NuGet Packages..." and search for and install the Microsoft.Toolkit.Uwp.Notifications NuGet package version 7.0 or greater.
Within your Visual Studio solution, right click your project, click "Manage NuGet Packages..." and search for and install the Microsoft.Toolkit.Uwp.Notifications NuGet package version 7.0 or greater.