Changing text box to auto size

I'm working in Acrobat Pro DC version 2019 and I need to change a "text box" to automatically resize text to fit the box (so when you print it shows all the text).  This is in an existing form.  The form will only allow me to change font sizes of the form field headers, form instructions, etc. but not the actual box when you want people to type.  Does anyone know how to do this?  Thank you.