1. Go to Communities > Forms > Registration > Your Form
  2. Hover over form name and click Website Info
  3. Click Registration Form Options
  4. Click Edit next to registration type
  5. On the General Information tab, update the quantity.  Note: This defines the number of registrations received with one purchase of this registration type. 
  6. Click on the Advanced tab
  7. Mark the box next to collect guest information
  8. Click Save