Reading App for PDF docs - good size font, visible pictures, no horizontal scrolling

[Emil Bakeev]

I mainly use Kindle and iBooks for books reading, but most of my books are in PDF format. When the text is in small font, I increase the size, but then I am forced to scroll horizontally. Pictures also increase in size. My father says that he has some app on his Android that allows him to read books with good font size without need to scroll horizontally. Is there an app that can do similar things? It is possible that my father is confusing though.
Thanks