Simplex accepts Apple Pay as an additional payment method.
Once you reach the checkout, you can choose the Apple Pay option - this way, you will not need to fill in your card details manually.
You can click the Apple Pay button, then "Select your card", and agree to the terms and conditions - now you are all set.
The limits for using Apple Pay are the same as those for using VISA or MasterCard - the daily transaction limit is 20,000 USD, and the monthly limit is 50,000 USD.
You can use Apple Pay with 16 fiat currencies - USD, EUR, GBP, CAD, JPY, CHF, KRW, DKK, PLN, SEK, ZAR, CZK, NZF, HKD, NOK, SGD.
You can find countries and regions that support Apple Pay here: https://support.apple.com/en-us/HT207957.