[NumLock]

Код:

var
  hFile: THandle;
  str: String;
  NumberOfBytesWritten: DWORD;
begin
  str:='Привет, Siri'+sLineBreak;
  hFile:=CreateFile('Unit1.txt', GENERIC_WRITE, 0, nil, OPEN_ALWAYS, 0, 0);
  if hFile<>INVALID_HANDLE_VALUE then
  begin
    SetFilePointer(hFile, 0, nil, FILE_END);
    WriteFile(hFile, str[1], Length(str), NumberOfBytesWritten, nil);
    CloseHandle(hFile);
  end;
end;