The data that a VPN collects about you depends on the specific VPN service you are using. In general, VPNs collect data about your device, such as your IP address, the type of device you are using, and your operating system. They may also collect data about your online activities, such as the websites you visit and the files you download. Some VPNs may also collect data about your location and the duration of your VPN sessions. It is important to carefully read the privacy policy of a VPN service before using it, so you know what data they collect and how they use it.