Pax Dollar was previously called Paxos Standard and is a stablecoin token based on Ethereum. With the rebranding, it changed its trading ticker from PAX to USDP to better fit the other USD-backed stablecoins on the market. Regardless of the branding, PAX and USDP denominate the same token on the same contract.
Pax Dollar is issued by Paxos, a financial company that manages the product. They maintain that in addition to being licensed and audited, Pax Dollar is also fully regulated. The supply and issuance of USDP are managed by Paxos so that the circulating supply of USDP is always equal to the USD in their reserves. By keeping this balance, Paxos ensures that USDP is always redeemable for USD in a 1:1 ratio.
As a dollar-backed stablecoin, USDP can be used as a digital currency for global transfers and frictionless payments. USDP is issued on the Ethereum blockchain as a fungible token.