Thanks! ^^ On PC I believe it's by pressing "H" and hitting it again to display it once again when you wish.
If you're on Android we're currently looking into fixing our gui this Summer as there's no way that we're aware of to hide textbox on that version. The plan is to sometime this Summer do a gui overhaul and with it, we'll see a show/hide button next to the textbox that'll make it much simpler for all. (Along with plans to ensure our mobile gui is sized properly)
Glad you're enjoying everything though! Miki is always fun to have pop up and see just what she'll do next. :P