An amber light on an AirPods charging case can mean different things depending on whether the AirPods are inside the case.
When the AirPods are in the case and the lid is open, the status light generally shows the charge status of the AirPods. When they are removed, the light instead shows the status of the case itself.
An amber light normally indicates that the relevant battery is not fully charged. A green light indicates a full charge.
The location of the status light varies between AirPods and charging case models. On some cases it is on the front, while older Lightning Charging Cases place it inside beneath the lid.
If the light flashes amber rather than remaining steadily illuminated, that can indicate a setup or pairing issue rather than simply a low charge. Reconnecting or resetting the AirPods may be required if pairing continues to fail.
The easiest way to see an exact battery percentage is to bring the AirPods close to a connected iPhone or check the Batteries widget, rather than relying solely on the case light.