In the vSphere Client, the Version 9+ Licenses section under the Administration menu does not have a way to license the vCenter, or might show "No Licenses Found"
vCenter 9.0 appears to be stuck in evaluation mode without the ability to apply a license.
vCenter 9.0
This is by design. vCenter no longer handles the licensing of a 9.0 environment. This is now managed through VCF Operations.
Licensing a vCenter requires an existing VCF Operations 9.0 appliance, and for it to be associated with the vCenter via either a VMware vSphere Foundation (VVF) or VMware Cloud Foundation (VCF) deployment.
For air-gapped environment with SDDC manager and VCFO is not in use , the process is :
Download the operations-appliance OVA file from the Broadcom Support Portal.
Deploy the Operations Appliance
Complete Configuration.
Register and License the vCenter in disconnected mode
Assign the license to vCenter.
Please refer to the following kb articles :
Upgrade and Downgrade VMware License Keys via the Broadcom support portal
Unable to license vCenter after upgrading to 9.0