Apple's Print Product stores have been closed last year, at the end of September. You can no longer order cards, calendars, books, prints, from Apple. In the newer versions of Photos the tools to create Apple books etc have been removed from Photos. On macOS Sierra they are still there, but you cannot order the finished products from Apple.
To get your calendar printed, save it as a PDF file and upload it to a service, that can print from Apple PDFs, see: https://discussions.apple.com/docs/DOC-250000261
We have now to use third-party services to order books and other print projects.
Newer versions of Photos (since Photos 3.0) come with the ability to call third-party project extensions from Photos to let us create books or other print projects.
Use Project Extensions to order print products in Photos after September 30, 2018 - Apple Support
"To give users access to a broader variety of print services, macOS High Sierra introduced Photos Project Extensions which integrate directly with the Photos app. In macOS Mojave, Photos will transition entirely to Photos Project Extensions. Users will be able to print and update their existing projects using these new services, and will gain access to a broader variety of options. For final purchases using the existing built-in service, place your orders by September 30, 2018. "
- If your Mac can be upgraded to macOS 10.13 with Photos 3.0 or newer, you can use the project extensions to create the print projects. Or try to convert your existing project with project extensions to a new format. Be sure to make a backup copy of your Photos Library (and your Mac), before you try the upgrade to a new system version.
To check the compatibility of your Mac with newer system versions and Photos 3.0 or 4.0:
But before upgrading to Photos 4.0 you should be aware, that Photos 4.0 has no longer any native built-in support to create books or calendars at all. Apple removed these tools in favor of the third-party extension. As a consequence, you cannot create a book or calendar PDF any longer with the previous tools, while working off-line. The extensions need an internet connection and do not allow to save a PDF version. If you want to have PDF versions of a book or want to to be able to work on a book off-line, you could try the PrestoPhotos.app to create your book in Pages: https://www.prestophoto.com/help/PrestoPhoto+App