uses
  RichEdit;
 // Using the Paragraph property
procedure RE_AlignText1(ARichEdit: TRichEdit; alignment: TAlignment);
 begin
  ARichEdit.Paragraph.Alignment := alignment;
 end;
 // Using PARAFORMAT2; nonVCL
procedure RE_AlignText2(ARichEdit: TRichEdit; alignment: TAlignment);
 var
  pf2: PARAFORMAT2;
 begin
  FillChar(pf2, SizeOf(pf2), 0);
  pf2.cbSize := SizeOf(PARAFORMAT2);
  SendMessage(ARichEdit.Handle, EM_GETPARAFORMAT, 0, Longint(@pf2));
  pf2.dwMask := PFM_ALIGNMENT;
  case alignment of
  taLeftJustify: pf2.wAlignment := PFA_LEFT;
  taCenter: pf2.wAlignment := PFA_CENTER;
  taRightJustify: pf2.wAlignment := PFA_RIGHT;
  end;
  SendMessage(ARichEdit.Handle, EM_SETPARAFORMAT, 0, Longint(@pf2));
 end;
 // Example: Right align text
// Beispiel: Text rechtsbundig ausrichten
procedure TForm1.Button1Click(Sender: TObject);
 begin
  RE_AlignText2(RichEdit1, taRightJustify);
 end;