You must trade it with it holding a Magmarizer.
Magby evolves into Magmar at Level 30.
You need to trade it when it's holding a Magmarizer to evolve it into Magmortar.
Magmar does not evolve at any specific level. Magmar evolves when traded with a magmorizer. Magmar will evolve into a Magmortar if you trade it to someone else while it's holding a magmorizer.
you trade it with a magmarizer
Level 30 into magmar
Magby requires Level 30 to evolve into Magmar and then trade it while holding the Magmarizer to evolve Magmar into Magmortar in Pokemon Diamond/Pearl. Magby can be found on Route 227 in Pokemon Diamond.
Magmar doesn't evolve in Pokemon Red, Blue, Yellow, Green, Silver, Gold, Crystal, Ruby, Sapphire, Emerald, FireRed, or GreenLeaf. It can only evolve in the newer Pokemon games.
Magmar does not evolve in XD since its evolution was first introduced in Pokémon Diamond and Pearl.
Magby will start to evolve into Magmar as soon as it hits Level 30.
Emolga does not evolve. I played Pokemon White also and it does not evolve. Some Pokemon do but this one does not evolve.
strictly speaking it doesn't, you have to trade it holding a magmarizer to make it evolve into a magmortar
Magby evolves by leveling and it'll start to evolve into Magmar at Level 30.