I want to send information from textbox1 in (form1) to textbox2 in (form2) .
How can i do it?
please hellp me
thank you

There are many ways to do that. Try this:

In Form2, set the Modifiers property of textbox1 to "Public". If you want to get access to Form1's textbox in Form2 then also do this for the textbox in Form1. (screenshot)

And use this code in Form1:

Form2 form2;

        public Form1()

            form2 = new Form2();

            // You can send info to Form2's textbox this way:
            form2.textBox1.Text = "set text";