How to save a PDF from the net
How do I save a PDF file from Safari to my iPad?
iPad, iOS 7.1.1
Do you have an app on your iPad that supports PDF files e.g. iBooks, GoodReader, Adobe Reader etc - an iPad doesn't have a 'file system' like a computer, everything has to be stored in an app.
If you do then open the PDF in Safari and then tap on the PDF and you should get an 'open in' option show at the top of the screen allowing you to save it to your PDF app.