You can't.
You can, however, catch a Magmar inside the Burnt Tower in Ecruteak City and breed it with another Magmar (of the opposite sex) or with a Ditto.
If you have a female Magmar, you can also breed with the following (male) Pokémon:
Abra, Alakazam, Drowzee, Electabuzz, Hitmonchan, Hitmonlee, Hitmontop, Hypno, Jynx, Kadabra, Machamp, Machoke, Machop and Mr. Mime.
You can catch Magby by Feugo Ironworks.
You can catch magby in the white forest
Sorry you can't catch magby, but you can still breed magby with magmar.
yes
level 30
you can by getting an egg
Catch a wild magby
White Forest
magby can be found in the western (right) side of Pueltown
Of course, throwing Pokéball at it...
Wild Magby occasionally hold them. You can catch Magby at Stark Mountain.
you might mean magby. You can go to Fuego Ironworks and you can find a magmar. you can breed it and get a magby egg.