How can i write something

ROOT
1

Hi rooters.
How can i write something(example:Cf) in a Pad(inside of coordinate system)? (not as title)
Thanks all.

2 
{
   TF1 fun1("x*x","x*x",-1,1);
   fun1.Draw();
   TLatex l;
   l.DrawLatex(-0.35,0.8,"Hello World");
}