There are many options to get bitcoins, here are some known methods to get bitcoin.
There are many mining soft wares to get bitcoin. In this method electricity is consumed to solve complex mathematical equations and in return we get bitcoins. The famous and valid bitcoin mining software is antminer S9 to get the bitcoins.
There are also many exchanges to get bitcoin. Exchanges exchange bitcoin with other currencies. Many exchangers are also available in big cities where they exchange with hard cash. example of bitcoin exchange is eobot.
There are also many faucets who claim that they give bitcoin free in return of some kind of work on their sites but this method is not valid because they pay so little that when it reaches threshold they quit. example is faucethub.