How to send SMS using FASTSMS in c# windows application

    private void button1_Click(object sender, EventArgs e)
    {
        try
        {
            webBrowser1.Navigate("https://www.fast2sms.com/dev/wallet?authorization=[API KEY]&sender_id=FSTSMS&message='"+textBox2.Text+"'&route=p&numbers='"+textBox1.Text+"'");
        }
        catch (Exception ex)
        { 

        }

    }

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I need to send sms using C# windows application by FAST2SMS

I am using a webbrowser tool in c# to navigate,