download-folder.psm1

function Get-DownloadFolderPath() {
    $SHGetKnownFolderPathSignature = @'
    [DllImport("shell32.dll", CharSet = CharSet.Unicode)]
    public extern static int SHGetKnownFolderPath(
        ref Guid folderId,
        uint flags,
        IntPtr token,
        out IntPtr lpszProfilePath);
'@

    $GetKnownFoldersType = Add-Type -MemberDefinition $SHGetKnownFolderPathSignature -Name 'GetKnownFolders' -Namespace 'SHGetKnownFolderPath' -Using "System.Text" -PassThru
    $folderNameptr = [intptr]::Zero
    [void]$GetKnownFoldersType::SHGetKnownFolderPath([Ref]"374DE290-123F-4565-9164-39C4925E467B", 0, 0, [ref]$folderNameptr)
    $folderName = [System.Runtime.InteropServices.Marshal]::PtrToStringUni($folderNameptr)
    [System.Runtime.InteropServices.Marshal]::FreeCoTaskMem($folderNameptr)
    $folderName
}

Export-ModuleMember -Function Get-DownloadFolderPath