Hello Sailaja,
you can code like this,
Response.Cookies["userName"].Value = "Username";
Response.Cookies["userName"].Expires = DateTime.Now.AddDays(10);
Response.Cookies["domain"].Domain = "Codeproject.com";
if(Request.Cookies["userName"] != null)
lblUserName.Text = Server.HtmlEncode(Request.Cookies["userName"].Value);
Note:No sensitive information should be stored in a cookie.
All the Best:)