The nametag holders are flat on the top of the canopy when it is open. They write your name on one and give it to you when you rent, though of course you can make your own, I guess. If it's for identification, though, a good way to identify your stroller quickly is to tie a ribbon, scarf, bandana etc. on the handle.
When your stroller is one of a crowd of 75 parked outside the Aladdin show, for example, it's hard to search through to pick out your name very easily. But if you have, e.g., a bright orange bandana knotted to the handle, it stands out like a beacon and you find it very quickly. We did this with ours, and it worked great.