Create Forms doesn't ask for "Requires Signature"

I was working with someone today, who needed to create a form with signature requirements. She's using Acrobat 2017. When choosing to run the Create Form dialog box, she did not get the option to check "This document requires signatures", which brings up a whole 'nother set of form tools, including signature fields and signature boxes which have pre-created verification options included.

This question's been asked a lot of times, and never been answered. I can't help her - on my computer, this option works just fine. She's on a Windows 10 Enterprise edition machine, with Acrobat 2017. Anybody have any ideas? Thanks!