Many people would first think about Parkinson's when they see hand tremor(hand shaking), but the majority of patients with hand shaking are having essential tremor, only around 2% of hand tremor is Parkinson's disease.
There's a difference between essential tremor and tremor caused by Parkinson's. You can observe at home on your own.
Essential tremor: hand shakes when holding something
Parkinson's tremor: hand shakes when it's not holding anything, but hand doens't shake or shakes much less obviously when it's holding something. It's called tremor at rest.
If you notice it's tremor at rest, please get support from your doctor. Certain exams are necessary in order to diagnose. Parkinson's disease can't be cured but medications can help manage the tremor in walking or moving and improve the patients' quality of life.
Essential tremor usually doesn't affect much on daily life, however, patients with essential tremor have a 3-5 times higher chance of developing into Parkinson's.