possible to have a editable Textfield inGame (MessageBoard)?

Hello,
well i want that the User can go in Game to a MessageBoard and Post a Message.
Is this possible and what do i use for it ?

The Story is:
The User is walking in the Game around…
… and finally seeing this Messageboard.
if the Player klick on the MessageBoard then he can post also a Message.

many thanxx
kerstin
:sweat_smile: