[OTTEPAHD]

Код:

var
  Form1: TForm1;

var
 Source, Dest: String;
 i: Integer;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
  Source := Edit1.Text;
  Dest := '';

    for i := 1 to Length(Source) do
   begin
    if Source[i] in ['A'..'Z', 'a'..'z', 'А'..'Я', 'а'..'я'] then
    Dest := Dest + Source[i];
    Edit1.Text:=Dest;
    Dest:='';
    Edit1.Text:=ANSILowerCase(Edit1.Text);
   end;
   
end;

end.

вот так использую