Yes, you can win money, and you can lose money. It is random. More people lose than win. Otherwise, the casino would not be able to offer the service.
Even if some people win big, or hit the jackpot, making money on casino should not be your primary reason to play.  Online Gambling is an entertainment form that should be enjoyed with responsibility.
How it works:
Casino sites utilizes RNG (random number generators) to produce results. If lady luck is on your side, you can win money but you can also lose money.
All games have an average RTP (return to player). This is how much on average is returned to the player.
As an example, slots usually have an RTP of 93-99%. This means if you play for ₹100, on average you will win ₹93-99.