What sources of funds can be used for peer-to-peer Apple Pay? Peer-to-peer Apple Pay was announced during the 2017 WWDC keynote.

How does the money enter your Apple Pay account in the first place?


Does it come from a linked credit card, as in how Apple Pay traditionally  works?  If so, would the transaction be considered a cash advance or a purchase by the credit card company?
Does it come from a linked bank account or a linked debit card?  If so, does that mean giving Apple a pre-authorization to withdraw money from your bank account?  Also, is there an imposed or customizable limit to how much money can be withdrawn?
Do you buy credits to be added to your Apple Pay account using gift cards, at a convenience store or at an Apple Store?
Apple Pay Cash is being introduced in the US first, with iOS 11.2 and watchOS 4.2 betas.  Both parties in a peer-to-peer transaction must have a suitable version of the software and have signed up for Apple Pay Cash.

Cash can be sent from a linked credit card (which incurs a 3% fee) or debit card.

Received cash is stored in an Apple Pay Cash card in Wallet.  It can be used for purchases or sent to a bank account.