PictureBoxに文字列を描画する例です。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            pictureBox1.BackColor = Color.White;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            using (Graphics g = pictureBox1.CreateGraphics())
            {
                using (Font font = new Font("MS ゴシック", 24))
                {
                    g.DrawString("てすと", font, Brushes.Black, 0, 0);
                }
            }
        }
    }
}