you find magmar in the burned tower in ercuteak city
burned tower
You must trade Magmar while holding the Magmarizer
If you breed magmar and ditto, you will get and egg that will hatch into magby.
u need to treade it with a magmarizer
If you have a magmar with you on your team that will help.
in soul silver, you can get magmar in the burned tower. then i guess you can just evolve it
You can use a cheat. Otherwise, there is no way.
in a volcanoe
You catch magmar at the burned tower at Eaurtek city.
Magmar > trade w/ Electrizer > Magmortar
Try to get these Pokemon :Magmar Pidgeot and any electric Pokemon with a good move like charge beam feraligatr also helps.
To obtain a Magby in Pokemon Soul Silver you first have to capture a Magmar and bread him with a captured Ditto. You have to breed these two Pokemon at the daycare center.