Which document must contain the signature and license number of the authorized licensee?

The service tag is the correct document that must include the signature and license number of the authorized licensee. This tag is placed on the fire extinguisher itself, indicating that the extinguisher has been properly serviced or inspected by a qualified individual. The signature and license number serve to validate the work performed and ensure compliance with local regulations and safety standards.

The installation certificate is typically related to the initial setup of the fire extinguisher system but does not necessarily require the licensee's signature for ongoing servicing. The inspection report is important for record-keeping and compliance but generally does not always need to be attached directly to the extinguisher. The warranty document is related to the manufacturer's guarantee for the product and does not pertain to the servicing or licensing of the technician. Thus, the service tag is the key document that ensures accountability and traceability of maintenance performed on the fire extinguisher.