Apple is discontinuing its Photo Print Products service, which has been integrated into iPhoto since its launch in 2002. The service expanded from simple prints, to albums, photo books, and calendars. It stayed around on the Mac when iPhoto was replaced with the Photos app a couple of years ago, but the service never made the leap to iOS.
Later this year, Apple will stop offering the service altogether. A new message in macOS 10.13.6 Photos app says that final orders for Apple’s built-in service must be placed by September 30, 2018.
In macOS Mojave, Photos already does not include any references to Apple’s integrated Photo Print Products service.
Apple’s recommendation is that customers download a third-party app that includes a Photos Projects extension. This API was introduced in High Sierra, and allows photo services to integrate photo printing UI inside the Apple Photos app. Payment processing and printing is all handled by the third-party.
Services that support Photos Projects include Mimeo Photos, Wix, GoodTimes, WhiteWall and Shutterfly.
Source: 9to5mac