How to review macOS 10.12 Server documentation without installing?
Apple does not bundle any PDFs with macOS 10.12 Sierra Server.

A standalone macOS 10.12 Sierra Server installer does not exist. Server.app is just an app which is downloaded from the Mac App Store.



The 'Help' Menu in Server.app has an entry called 'Server Help' which forwards to https://help.apple.com/serverapp/mac/5.3/index.html .

The macOS server requirements are available in the Server Help as well. The checklist Install macOS Server may be helpful as well.