To enable VPN in Opera, first open the Opera browser and click the O menu in the top-left corner. Then, navigate to Settings. Scroll down to the Privacy & Security section, where you'll find the option to enable VPN. Toggle the Enable VPN switch to the ON position. Once activated, the VPN will be visible in the address bar, indicating that your connection is secure and masked. This feature allows you to browse the web with enhanced privacy and access content from different regions.