The credit card reader connects to your iPhone via Bluetooth and allows you ... including Sum Up, Zettle by PayPal, Worldpay, Yoco, Ezetap, Tyro, SmartPay, PayGate and SB Payment Service.
So long as it's an iPhone XS or newer, no additional hardware is required — no dongles or Bluetooth card readers are needed ... That's what PayPal and Venmo have now done.