Does a VPN protect you?

Excuse me, I've heard a lot about VPNs and how they can help protect online privacy. But does a VPN really protect you? Can't hackers still intercept my data even if I'm using a VPN? And how does a VPN work, exactly? I'm a bit confused about the technology behind it. Could you please explain it to me in a simple way? I'd really appreciate it if you could answer these questions for me.