Are you looking for postage labels that simply have the name and address of the sender and receiver? Or are you looking for postage labels with actual postage attached?
If you simply want labels with names and addresses, you can generate them with a Block if you have a Pro account.
If you want more complex postage labels, you can see if Zapier can integrate Airtable with an online shipping service. For example, a quick search of the Zapier website shows that they can integrate Airtable with with Easyship. When you create a new record for a shipment in Airtable, Zapier would create a new shipment in Easyship with the details from Airtable, and then you could print your label from Easyship. (I have no actual experience with Easyship. I am simply repeating info from their website.)