The following example uses the Windows API function PrintDlg() to allow the user to choose a printer and prints two pages using the returned dc. Example:

uses CommDlg;
{$IFNDEF WIN32}
 const MAX_PATH =  44;
{$ENDIF}
procedure TForm .Button Click(Sender: TObject);
var
  Pd : TPrintDlg;
  DocInfo: TDocInfo;
begin
  FillChar(Pd, sizeof(Pd), #0); 
  Pd.lStructSize := sizeof(Pd);
  Pd.hWndOwner := Form .Handle;
  Pd.Flags := PD_RETURNDC;
  if PrintDlg(pd) then begin
    FillChar(DocInfo, sizeof(DocInfo), #0);
    DocInfo.cbSize := SizeOf(DocInfo);
    GetMem(DocInfo.lpszDocName, 32);
    GetMem(DocInfo.lpszOutput, MAX_PATH);
    lStrCpy(DocInfo.lpszDocName, 'My Document');
   {Add this line to print to a file }
    lStrCpy(DocInfo.lpszOutput, 'C:\Download\Test.doc');
    StartDoc(Pd.hDc, DocInfo);
    StartPage(Pd.hDc);
    TextOut(Pd.hDc,  00,  00, 'Page  ', 6);
    EndPage(Pd.hDc);
    StartPage(Pd.hDc);
    TextOut(Pd.hDc,  00,  00, 'Page 2', 6);
    EndPage(Pd.hDc);
    EndDoc(Pd.hDc);
    FreeMem(DocInfo.lpszDocName, 32);
    FreeMem(DocInfo.lpszOutput, MAX_PATH);
  end;
end;