I think majority usually just rent the services instead of buying and keeping.
Maintenance is a pain

Might be a bit too late to reply, what kind of boat are you talking about? Usually, anglers prefer soft inflatable boat. 380mm in length, paired with a 10HP outboard motor.
To answer your question, inflatable boats can be kept indoors (as long as you have the space) but the outboard motor, if you live in a high rise, you might need to make a deal with your building management on storing it. Get an outboard trolley to hang it.

Transporting inflatable boats, you can either use roof rack if it is fully inflated or if it's folded in its bag, inside the car. Mind you, it will take a bit of space even when fully folded.
The outboard you will need to make space for it inside your car.

If you're talking about fiber boats, you need to get in touch with jetties to park the boat. It'll cost you around RM200-300 per month I think (not too sure, you'll need to build rapport and ask around). This restricts your fishing area though.

p/s: Just keep in mind that even with a boat, if you do not know the fishing spots, it is of no use. You'll be devastated because you spent a whole lot of money but went home skunk. My advice is to rent first. See how do you like it. If it is your first time, get somebody who knows how to handle boats. Don't go being super positive that you can handle a rented boat. Any damages will be expensive.