Update Request System Generated Form?


Hello all. I sent out update requests last week and most of the recipients had multiple line items to update. I was surprised to see an 'Open Form' icon in the message but even more surprised to find that when I clicked it, a form popped up with the name of the line item allowing me to enter the comments THEN to go to the next one on the update request! It is a wonderful feature but I need to know how to remove fields from it and to make certain fields required. I checked my 'forms' and do not have any for this sheet. I am guessing I am not looking in the correct place?