Hi!
There are no builtin GUI text input elements, but you could take a look at my mini-library: DirtyLarry - A quick and dirty GUI library
In summary:
The input “element” is just a text GUI node. I check for mouse clicks/touches on this node and show the system keyboard if this happen (gui.show_keyboard()). When any “text input” is received, I update the content of the text node (gui.set_text()).