Opacity

Opacity 70%

Opacity 100%

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

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

private void Form1_Load(object sender, EventArgs e)
{
Opacity = 0.70;
}

private void textBox1_TextChanged(object sender, EventArgs e)
{

}
}
}