ESC / POS commands EPSON printer basic format functions in C #

Good afternoon

Ando lost in a topic about impressions, basically I have to print some text, but I can not give the desired format and I do not understand well how the ESC / POS commands work, I have the following code:

SerialPort sp;
        sp = new SerialPort();
        sp.PortName = "COM1";
        sp.BaudRate = 9600;
        sp.Parity = Parity.None;
        sp.DataBits = 8;
        sp.StopBits = StopBits.One;
        sp.Handshake = Handshake.RequestToSend;
        sp.DtrEnable = true;
        sp.RtsEnable = true;

        sp.Encoding = System.Text.Encoding.UTF7;

        sp.Open();

        if (!sp.IsOpen)
        {
            MessageBox.Show("Puerto serial no es soportado.");
            return;
        }

        sp.WriteLine((char)27 + "E" + "This is Bold" + (char)27 + "F" + Environment.NewLine);
        sp.WriteLine("La opción de: " + "[CRÉDITO VEHICULAR]" + " se ha activado correctamente." + Environment.NewLine);
        sp.WriteLine("Los datos consignados para la operación, son los siguientes:" + Environment.NewLine);
        sp.WriteLine("Nombre Completo: " + Environment.NewLine);
        sp.WriteLine("DNI: " + Environment.NewLine);
        sp.WriteLine("Fecha de operación: " + Environment.NewLine);
        sp.WriteLine("Correo de contacto:" + Environment.NewLine);
        sp.WriteLine(Environment.NewLine);
        sp.WriteLine("Los documentos del contrato ha sido enviados a su correo electrónico, indicado lineas arriba." + Environment.NewLine);
        sp.WriteLine("Sirvase ponerse en contacto con nosotros a los siguientes números:" + Environment.NewLine);
        sp.WriteLine("" + Environment.NewLine);
        sp.WriteLine("[CÓDIGO DE BARRA]" + Environment.NewLine);

        sp.Write(CutPaper, 0, CutPaper.Length);
        byte[] data = new byte[sp.BytesToRead];
        sp.Read(data, 0, data.Length);

        this.Close();

That way I do not know how to put the code so that certain letters are in bold.

Also looking for another way, using a library: ThermalDotNet, with the following code:

string printerPortName = "COM1";

        SerialPort printerPort = new SerialPort(printerPortName, 9600);

        if (printerPort != null)
        {
            Console.WriteLine("Puerto OK");
            if (printerPort.IsOpen)
            {
                printerPort.Close();
            }
        }

        Console.WriteLine("Abriendo puerto");

        try
        {
            printerPort.Open();
        }
        catch
        {
            Console.WriteLine("I/O error");
            Environment.Exit(0);
        }

        //Printer init
        ThermalPrinter printer = new ThermalPrinter(printerPort, 2, 180, 2);
        printer.WakeUp();
        Console.WriteLine(printer.ToString());

        //TestReceipt(printer);

        printer.WriteLineSleepTimeMs = 200;

        printer.WriteLine("Default style");
        printer.WriteLine("PrintingStyle.Bold", ThermalPrinter.PrintingStyle.Bold);
        printer.WriteLine("PrintingStyle.DeleteLine", ThermalPrinter.PrintingStyle.DeleteLine);
        printer.WriteLine("PrintingStyle.DoubleHeight", ThermalPrinter.PrintingStyle.DoubleHeight);
        printer.WriteLine("PrintingStyle.DoubleWidth", ThermalPrinter.PrintingStyle.DoubleWidth);
        printer.WriteLine("PrintingStyle.Reverse", ThermalPrinter.PrintingStyle.Reverse);
        //printer.WriteLine("PrintingStyle.Underline", ThermalPrinter.PrintingStyle.Underline);
        //printer.WriteLine("PrintingStyle.Updown", ThermalPrinter.PrintingStyle.Updown);
        //printer.WriteLine("PrintingStyle.ThickUnderline", ThermalPrinter.PrintingStyle.ThickUnderline);
        printer.SetAlignCenter();
        printer.WriteLine("BIG TEXT!", ((byte)ThermalPrinter.PrintingStyle.Bold +
            (byte)ThermalPrinter.PrintingStyle.DoubleHeight +
            (byte)ThermalPrinter.PrintingStyle.DoubleWidth));
        printer.SetAlignLeft();
        printer.WriteLine("Default style again");

        printer.WriteLine({ ESC, 0x69 }, 0);
        printer.LineFeed(3);
        printer.Sleep();
        Console.WriteLine("Printer is now offline.");
        printerPort.Close();

With this last code, if I can see the format, but at the time of printing, the sheet does not cut it or eject it, this seems even worse to me.

I hope you can help me. Thanks