PDF is short for Portable Document Format. Itâs a format designed for printing on paper. Although it can be read on screen it doesnât work well on smaller screens because the text is usually too small. To read it you must magnify it and since the text does not flow that means the reader must scroll the page in two directions to read it all. This makes for an unsatisfactory reading experience. If you MUST read a PDF file then read it on a device with a large high resolution screen An iPad Pro or MS Surface Pro is ideal for this. PDF is a format favored by those who pirate ebooks because t are easy to create. Books are scanned and the PDF produced is essentially an image. File sizes can be large. By downloading pirated ebooks you may be breaking the law in your country - especially if you download from a torrent server. Fines can be large and jail time is possible if you are caught. You are effectively stealing the authorâs royalties. PDF files may conceal malware which will infect your computer. The sites offering the files often ask for a registration fee for unlimited use of the site. Since many are pirate sites giving your payment details to a criminal is not exactly good sense. Added to that many of these sites feature adverts of dubious quality which may expose your computer to further danger. PDF files do have a place if the book must have precisely placed images where the text position next to these is important. Art books and books with mathematical formulas are examples. Not all sites offering PDF files are offering pirated content. In general EPUB and MOBI files offer a better reading experience and are safer.
Hope this helps.