I want to download a PDF document full of charts and graphics. Pages won't load it. Will ibooks?

I have loaded Pages software on my ipad.

I received a PDF document via email as an attachment which I wanted to save. It was a small document, but with lots of graphics, the ipad offered me no no option to store in Pages.

What app could I download which the ipad would give as an option for storage from an email. Would ibooks do?

I already have winzip, but that didn't show as an option.

Any advice would be welcome. Thank you.