How i can determine when a process id (PID) is 32 or 64 bit application?

You can use the OpenProcess function to get a handle to the pid and then call the IsWow64Process function.

Remember that you must load the IsWow64Process function using the GetProcAddress function because some versions of Windows does not include this function.

Check this sample code

{$APPTYPE CONSOLE}

uses
  Windows,
  SysUtils;

type
  TIsWow64Process = function(Handle:THandle; var IsWow64 : BOOL) : BOOL; stdcall;
var
  IsWow64Process  : TIsWow64Process;

procedure Init_IsWow64Process;
var
  hKernel32      : Integer;
begin
  hKernel32 := LoadLibrary(kernel32);
  if (hKernel32 = 0) then RaiseLastOSError;
  try
    IsWow64Process := GetProcAddress(hkernel32, 'IsWow64Process');
  finally
    FreeLibrary(hKernel32);
  end;
end;

function PidIs64BitsProcess(dwProcessId: DWORD): Boolean;
var
  IsWow64        : BOOL;
  PidHandle      : THandle;
begin
  Result := False;
  if Assigned(IsWow64Process) then
  begin
    //check if the current app is running under WOW
    if IsWow64Process(GetCurrentProcess(), IsWow64) then
      Result := IsWow64
    else
      RaiseLastOSError;

    //the current delphi App is not running under wow64, so the current Window OS is 32 bit
    //and obviously all the apps are 32 bits.
    if not Result then Exit;

    PidHandle := OpenProcess(PROCESS_QUERY_INFORMATION,False,dwProcessId);
    if PidHandle > 0 then
    try
      if (IsWow64Process(PidHandle, IsWow64)) then
        Result := not IsWow64
      else
        RaiseLastOSError;
    finally
      CloseHandle(PidHandle);
    end;
  end;
end;


begin
  try
    Init_IsWow64Process;
    //here pass the pid which you want to check
    Writeln(BoolToStr(PidIs64BitsProcess(1940),True));
  except
    on E:Exception do
      Writeln(E.Classname, ': ', E.Message);
  end;
  Readln;
end.