Place and TextBox in your webbrowser and then place and button and afterthat
on click event of button write code that is shown below:

ArrayList webpages=new ArrayList(); 
private void btnsearch_Click(object sender, EventArgs e)
        {
            WebBrowser thisweb = GetCurrentWebBrowser();
            thisweb.Url = new Uri("http://search.msn.com/results.aspx?FORM=SMCRT&q=" + txtsearch.Text);//search url with MSN
            timer1.Enabled = true;
        }

private WebBrowser GetCurrentWebBrowser()//function to get details of current webpage
        {
            TabPage current_tab = tabControl1.SelectedTab;
            WebBrowser thispasge = (WebBrowser)webpages[tabpages.IndexOf(current_tab)];
            return thispasge;
        }

So like that u can use it easily in your own created web browser and GetCurrentWebBrowser() function is taken for purpose to take of current pages in web browser.

Thanking you