Have a User Account for MarketPress

On the "Your Shopping Cart" page of MarketPress, it asks if you already have User Account and provides a place for name and p/w. How does someone register with a name and password if the recommendation is NOT to force login. In another post: "But users might want to skip the process of entering their address, name etc every time they use your shop. So, they can choose to login on checkout and their details are automagically loaded for them. "

I don't see where they are asked to create a username and password. And there doesn't appear to a field to "create a user account' on the page that requests shipping information.

Sorry for being so dense. I'm sure I'm missing something very simple.