I have malocclusion. will rapid palatal expander will help me?

Depends: You will need to see an orthodontist to establish a real diagnosis of your malocclusion and the cause of it, it can be dental or skeletal.

Probably not: Rapid palatal expanders are most effective in childhood when used before the right and left halve of the palate have fused. Expanders can be slightly useful in adults but it would be best to ask your dentist or orthodontist.

Crossbite?: As an adult, if upper jaw too narrow compared to lower common rx is to make jaws match side-to-side with surgically assisted rapid palatal expansion. Let an orthodontist examine you and give you viable treatment alternatives. The orthodontist can tell you about all the wonderful things that can be done to help you.

No: At your age it is highly unlikely that a palatal expander will be effective. That said, i would discuss what can be done with an orthodontist.

Limited for adults: Expansion of the palate in adults is the subject of debate due to the palatal suture having fused in late teens, preventing expansion of the palatal shelves in adults. Research claiming success often fails to distinguish between true bone expansion and posterior tooth uprighting of collapsed posterior teeth (a common problem in adults). Ask your orthodontist.