Apple Pay is a payments (both mobile payment and digital wallet) service launched by Apple Inc. that lets apple users / customers make payments using an iPhone, Apple Watch, iPad or Mac.
Shopify Payments
Stripe
First Data Payeezy
Cyber Source
You also need to have a valid SSL certification.
List of countries that support Apple Pay:
United States
United Kingdom
Canada
Australia
China
Singapore
Switzerland
France
Hong Kong
Russia
New Zealand
Japan
Spain
Guernsey
Ireland
Isle of Man
Jersey
Taiwan
Italy
San Marino
Vatican City
You can also check this article for the latest updated list
If you meet both the above pre-requisites, please create a staff account for support@plobalapps.com (on your Shopify Admin Panel) and drop a line to the same email or your customer success manager to get Apple Pay integrated for your mobile app.