بسم الله الرحمن الرحيم
An employee of a company is wakil and representative in buying goods for the company. The sample which the supplier gives to the employee, he gives him thinking him as the representative and wakil of the company and gives it to present to the owner or authority of the company, hence it is mandatory for the employee of the company to present the sample to the owner or authority of the company and it is not lawful for him to use it personally.
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.