For whatever reason, even Apple's Owner's Manuals are DRMed to the point where you cannot make fucking PDFs from these documents. They can be found on the web, but they're actually updated on Apple Books first, from my experience, though they don't do so automatically. (Especially if you need current information on iOS, itself, be sure to back out of the iPhone User Guide every few days and hit the update button.)
For whatever reason, even Apple's Owner's Manuals are DRMed to the point where you cannot make fucking PDFs from these documents. They can be found on the web, but they're actually updated on Apple Books first, from my experience, though they don't do so automatically. (Especially if you need current information on iOS, itself, be sure to back out of the iPhone User Guide every few days and hit the update button.)
iWork
Pages User Guide
Keynote User Guide
Numbers User Guide