Is the patent applied for in China valid internationally?

If this refers to an ordinary patent application filed in the Chinese Intellectual Property Office (in fact, the Patent Office), then it is only valid in China (that is, any company infringing in China can be sued in China, but the object includes domestic or foreign companies), because the patent is regional. Generally speaking, the patent department of the government decides whether to approve the registration of a patent application.

However, even domestic applicants can go through the "PCT" procedures through the Chinese Intellectual Property Office, and get protection in several PCT member countries (the actual purpose is usually in several major industrial countries: the United States, Japan and the European Union) on the basis of a patent priority date.

* Note: "PCT" is a patent cooperation treaty body under the World Intellectual Property Organization in Geneva, Switzerland.