Looked some more, and apparently there is no freehand drawing tools in Word for Mac 2016.
Otherwise, you would see a Drawing tab (which has replaced the Ink tab now in Office).
But, I do see some possible reference that if you have an actual drawing tablet (such as Wacom) attached, there are drawing tools that are activated with an actual drawing input device with Office for Mac - but I don't have one to test that theory. I don't think a trackpad, such as on your MBPro, qualifies as a drawing tablet.
In that case, you will need Office running on Windows, which is easy enough to do on your Mac, and Boot Camp.