Final answer:
The correct form that accompanies materials purchased from a commercial source for the Department of Defense (DoD) is DD Form 1348-6, which is an order form used to specify details for procuring supplies.
Step-by-step explanation:
The form that accompanies material purchased from a commercial source is DD Form 1348-6. This form is utilized by the Department of Defense (DoD) when procuring items from commercial vendors. It serves as an order form for supplies, parts, and equipment outside the standard military supply system. When using this form, the requisitioner specifies the necessary details such as National Stock Number (NSN), item description, unit of issue, quantity, and so on, to ensure the correct items are procured.