If you're a current customer or evaluating FortiGate solutions, I recommend reaching out directly to Fortinet or an authorized partner for guidance on obtaining the appropriate licenses.
FortiGate Virtual Appliance (VM) licenses are essential for activating the full features of FortiGate next-generation firewalls running on virtual environments. These licenses determine the capabilities and the duration for which the FortiGate VM can provide threat protection, network security, and other advanced services. Fortigate Vm License File Free Download