procedure MThread.Execute;
var http:TIdHTTP;
    ssl: TIdSSLIOHandlerSocketOpenSSL; s:string;
begin
  inherited;

  try
  http:= TIdHTTP.create(nil);
  ssl:=  TIdSSLIOHandlerSocketOpenSSL.Create(nil);
  try
  with ssl do
  begin
     SSLOptions.Mode:= sslmUnassigned;
     SSLOptions.Method := sslvSSLv23;
  end;

  with http do
  begin
    //Response.KeepAlive:= true;
    Request.UserAgent:= 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.9) Gecko/20100101 Goanna/4.6 Firefox/68.9 PaleMoon/28.10.0';

    AllowCookies:=    true;
    HandleRedirects:= true;
    HTTPOptions:=    [hoForceEncodeParams];
    RedirectMaximum:= 100;
    ProxyParams.BasicAuthentication:= false;
    IOHandler:= ssl
  end;

  page:= http.get(url_); // тот самый, ранее сформированый в интерфейсе URL

  finally
    ssl. free;
    http.free;
  end;


  except
  // Здесь с некоторых пор имеем "Connection Closed Gracefully"
  on E: Exception do
       messagebox(0,pchar(E.ClassName+': '+E.Message),pchar(''),MB_ICONWARNING+MB_OK); 

  end;
end;

http.Request.UserName:= "login";
http.Request.Password:= "password";
page:= http.get(url_);

page:= http.post(url_, "файл с параметрами");