Books collection and PDF not appearing on iPhone

My imac desktop, my ipad and my iphone are all linked. I have created a new collection in Books on my Imac and added a file to it (a PDF). The collection and the book appears OK on my IMac and IPad but not on My Iphone. This is disturbing as I desperatyely want the book on my phone. The PDF File is even not in books. Can anyone help me please.

[Re-Titled by Moderator]

Original Title: Books on an iphone