Use literal control and Place literal control within Div control
if you are using Master Page It Would be better to write this code in master page's Page Load Event.
protected void Page_Load(object sender, EventArgs e)
{
string path = "YourTextFilePath";
if(!string.IsNullOrEmpty(path))
{
string[] readText = File.ReadAllLines(path);
StringBuilder strbuild = newStringBuilder();
foreach (string s in readText)
{
strbuild.Append(s);
strbuild.AppendLine();
}
Lit.Text = strbuild.ToString();
}
}