Log into your RealVNC account and navigate to . If your current plan is "Online Only," you must upgrade to a plan that includes offline licensing. Contact RealVNC sales if the option is not visible—offline keys are often a paid add-on.
Yes, RealVNC Server is pre-installed on Raspberry Pi OS (formerly Raspbian). However, offline activation requires the full version (not the Lite edition). Use the same request/response file process via terminal: sudo vnclicense --request-offline . realvnc offline license key