Pull Ups work the same as diapers do as they absorb pee but not as much as a regular diaper.
Pull Ups are a type of pull on diaper meant to catch small amounts of urine and poop in case the child who is potty training has an accident.
The Pull Ups can sometimes confuse a potty training child but not always.
It's sometimes best to just put the child in underwear and deal with accidents and use Pull Ups or a regular diaper at night.
My kids wore pull ups for awhile at night but they leaked and so I had them wear regular diapers instead as they are cheaper and more absorbent and kept the child and the child's bed dry.