Why do my palms sweat all day?

Hyperhidrosis. Suspect this has been lifelong problem in which case it is just you. If this is new might want to see doc to exclude meds or hyper .Autonomic state.
Palm sweating. There is a condition called hyperhidrosis which can lead to swelling of the palms. This has to do with sympathetic nerve chain. I would advise that she be evaluated by a thoracic surgeon, as there are procedures can be done to help with this problem.