(I WILL ANSWER THIS FROM FIRERED/LEAFGREEN POINT OF VIEW AS IT IS IN THAT CATEGORY XD)
You will need to go to Lavender town, and enter the ghost tower. While you work your way through the tower, you will be challenged by quite a few trainers, and ghosts will try to battle you. Its best to run away from these ghosts though, if you do not have a Silph Scope you will not be able to identify any of the ghosts, and therefore you cant battle/capture any of them. Once you have gotten to the top floor of the tower, there will be a staircase. You cannot go up it because a powerful ghost is blocking your way. You need the Silph scope for this task! The ghost will be a Marowak, which you can battle, and capture if you want to. Bear in mind that you need to go up the staircase afterwards, as your next task awaits!
Good luck :)
no.
You cant
You can't if you don't hack [Another User..] I heard you can capture legendary Pokemon on Pokemon indigo by beating all the gym leaders,kanto leaders and elite4 and you get a new map to capture them
Get more money and Capture them
Marowak cannot be caught in the wild in Pokemon Platinum. You'll need to capture a Cubone, which can be caught in Route 203 when there's a swarm of Cubone. (You'll need to talk to Lucas'/Dawn's sister in Sandgem Town) When it is captured, you can evolve it into a Marowak at level 28.
Marowak does not evolve.
Marowak doesn't evolve into anyone. Maybe you are confused with Cubone who evolves into Marowak
Marowak is #105 in the national pokedex, and it is a Ground type Pokemon.
Pokemon indigo does not exist
NO!
Pokemon indigo is a fake
If you really want a Marowak, you can get one by evolving a cubone or catching one on Victory Road.