Apple Wallet etickets and PDF etickets both have the same matrix barcode (which is an Aztec Code, if you’re interested). Apple Wallet etickets can be added to your Apple Wallet, so you can access them without opening Railboard. PDF etickets are easier to share and print.
You can use either at the ticket barriers; they both have the same matrix barcode.
You can access PDF etickets from the “Ticket details” screen, and use the button in the top right to share them.