http://zqktlw5bf6oycxq6qod452xnvdfcqhfwliz54bkul736g6b454jrk2ad.onion/wiki/index.php?title=Physical_Interaction
The form you have to fill out is Form 1583 and is universal among all CMRAs. It requires two forms of ID, one of them photo. The Privacy Statement is riddled with exceptions to allow the agent to provide information to "contractors", "financial entities", USPS auditors (who appear to be under no privacy obligation themselves), and for purposes of "identifying addresses... used to deliver mail to other persons".