display html from codebehind

 i want to just click on a button and more html code is added to my webpage from code behind .

I dont want to just display 1 textbox as it will not have a limit in theory.

i click on a button and at bottom on my main div class, i display

<h2>Teacher Version</h2>

everytime i click a button i display this, now this is a small example of what i want.
 
how do i do this?

...