Why is there a blank box on my iPad Air?

A blue outlined box that is blank inside is showing up at random times in the top right corner of my BRAND NEW iPad Air….when it appears, I can do nothing. The box takes up about a quarter of my screen….and cannot be moved or deleted. The only solution is to turn the iPad off and start again…..but I lose whatever I was working on each time it happens! Help!!

[Re-Titled by Moderator]