A virtual private network (VPN) is used to create a secure network connection over the internet. It encrypts users' internet traffic, masking their IP addresses and providing privacy while browsing or conducting online transactions. VPNs enable secure access to private networks and help bypass geo-restrictions, allowing users to access content from different regions. They are especially useful in safeguarding sensitive information when utilizing public networks or Wi-Fi. VPNs play a crucial role in enhancing online security and maintaining user anonymity in a connected world.