In your case 8.2.4 should be “The organization shall monitor and measure the characteristics of the service provided to verify that service requirements have been met”
First you have to know what are the requirements for your “materials delivery” service. Probably some requirements should be “on time delivery” and all other things related to the preservation of the materials.
As the standard says you have to monitor and measure “at appropriate stages of the product realization process”, you must plan inspection activities in order to assure that the requirements you considered before are being achieved.
I hope I’ve helped.