Sample code to display the Sharing Configuration UI (i.e., Give access to... > Specific people...)

MainWindow.xaml.cs

using System.Runtime.InteropServices;
using Windows.Win32;
using Windows.Win32.Foundation;
using Windows.Win32.UI.Shell;
using System.Windows;
using System.Windows.Interop;

namespace WpfApp10
{
    //
    // WARNING: Tested only on Windows vNext 27802.rs_prerelease.250222-1646
    //
    [Guid("14aa4ab8-abe3-4a07-a290-1d5dccdd2fc2")]
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    interface ISharingConfigurationUI
    {
        // ntshrui!CSharingConfiguration::CanShareItems(IShellItemArray *)
        HRESULT __CanShareItems__Stub();

        // ntshrui!CSharingConfiguration::ShowShareItemsUI(HWND *, IShellItemArray *)
        HRESULT ShowShareItemsUI(HWND hwnd, IShellItemArray items);

        // ntshrui!...
    }

    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private unsafe void Window_Loaded(object sender, RoutedEventArgs e)
        {
            var hwnd = new WindowInteropHelper(this).Handle;

            var idlist = PInvoke.ILCreateFromPath(@"C:\Temp");
            PInvoke.SHCreateShellItemArrayFromIDLists(1, &idlist, out var array);

            var config = (ISharingConfigurationUI)new SharingConfigurationManager();
            config.ShowShareItemsUI(new HWND(hwnd), array);

            PInvoke.ILFree(idlist);
        }
    }
}

NativeMethods.txt

HWND
IShellItemArray
ILCreateFromPath
ILFree
SharingConfigurationManager
SHCreateShellItemArrayFromIDLists