Individual donor companies manage their own approvals and shipping of physical products, so the easiest way to contact them with questions is through the "Direct Message" area in your match record.
Go to "My Matches" and click on the "Matched" tab.
Select the correct event at the top, then click on the name of the listing for the donation.
You will see a "New Direct Message" or "Direct Message" button near the top:
Click on this, and you can send your question directly to the company contact. When they reply, you will receive an email (if you did not remove message notifications) and see the notification on your dashboard.