Communication between projects

Hello guys, I already have a project created and consolidated, and I'm creating another project. I need to call the second project from the first one, passing a parameter, and the actions I do in the second project must be passed on to the first one.

Example. Project A calls Project B... waits for the user to close B, and whatever the user enters into B's textbox, it will return to project A.

private void button1_Click(object sender, EventArgs e)
        {
            
            string cPath = @"C:\Users\test";
            string filename = Path.Combine(cPath, "WinFormsApp3.exe");
            var proc = System.Diagnostics.Process.Start(filename, textBox1.Text, null, null, null);
            proc.CloseMainWindow();
            proc.Close();
        }

static void Main(string test)
        {
            if (string.IsNullOrWhiteSpace(test))
            {
                string arg1 = test;

                Application.SetHighDpiMode(HighDpiMode.SystemAware);
                Application.EnableVisualStyles();
                Application.SetCompatibleTextRenderingDefault(false);
                Application.Run(new Project2(arg1));
            }
            else
            {
                Application.SetHighDpiMode(HighDpiMode.SystemAware);
                Application.EnableVisualStyles();
                Application.SetCompatibleTextRenderingDefault(false);
                Application.Run(new Project2());
            }
        }