Not sure, but normally, you have to buy it. If you're advanced in hacking, you can try stealing it - not recommended, as you will be an @ole, lots of people will hate you, and you will probably die alone.
But if you're not a hacker, than the only ways I'm aware of, are to buy it for fiat, or to help someone and they would pay you in return in BTC, but most likely it is a case of buying it with fiat.
You really do not have to go the buying way if you have some skills to dish out in the community which obviously can make you earn a lot of it. So many people have been earning it over the years and some who started earlier would have been worth a lot by now.
Once you have some skill-set needed in the community, then you can really make shit load of bitcoin and even if you do not have skills, you can just make use of the little campaigns to still earn something good.