Hi there,
You can insert a Text entry box and define a variable (like I have used variable name as 'xyz1') for the text to be entered and validate the user input if you want,
And then on the slide where you want to show the content of the text entry box, insert a text caption there and use $$variablename$$, I have used $$xyz1$$ in my example"
Whenever this text caption will come up it will show the content of Text Entry Box. If you will uncheck the validate user input then you cannot include text entry box in quiz.
I hope you may find it helpful.
Thanks.