Editorial note: These apps are recommended for their usefulness to travelers. Some booking links on ChinaGoTrip may be affiliate links, as explained in our affiliate disclosure.

Plane Tickets / Train Tickets / Attractions Tickets
In China, there are official websites and apps for booking train and plane tickets:
Attraction tickets may be sold through an official website, an official WeChat mini program, or a major booking platform. The correct channel and foreign-passport support vary by attraction.
China Railway 12306 has an English website and app, but some local attraction channels remain Chinese-first.
Real-name services may ask for passport details or identity verification. Complete setup before tickets open whenever possible.
The China trains and transport guide explains passport verification, station names, boarding and local transport in one sequence.
So China Go Trip recommends the following app:

Trip.com
Book plane tickets, train tickets, and attractions tickets.
Payment Apps
The most popular payment method in China currently is digital payment. The most widely accepted ones are Alipay and WeChat Pay.