A VPN mostly protects you in two ways. The most basic way is by routing your internet traffic through one of its own servers — instead of through your local network or a public Wi-Fi hotspot — thereby masking where your traffic comes from.
VPNs also encrypt all of this traffic in a tunnel, obscuring all of your browsing content. VPNs help secure your browsing data against third-parties observers like hackers. All of the VPNs on this list are capable of doing this.