Huawei freelacepro headphone uses the Type-C plug charging mode. You can see the headphone plug by unplugging the plug switch marked with a red ring on the right collar.
Connect the headphone plug to the included Type-A to Type-C female adapter, then connect the other end of the adapter to a booted computer or a USB power adapter to the power supply.
When the headset is charging, the indicator flashes red or white light. Charging takes about 70 minutes to complete, and then the headphone indicator lights on in white. After charging is complete, you can disconnect the headset from the power supply.