Because pdf files can only be read but not written; Word files are both readable and writable. It is easy to understand that once a pdf file is formed, it cannot be modified, while a word file can be modified. In order to avoid calling papers from each other, many people choose to upload papers in pdf format. Generally, if you write a paper, you can only write it in word. At the same time, you can convert word into a pdf file when you finish your thesis.

PDF is the abbreviation of portable document format, which means "portable document format". It is a file format developed by Adobe Systems for file exchange, which has nothing to do with applications, operating systems and hardware. PDF file is based on PostScript language image model, which can ensure accurate color and accurate printing effect on any printer, that is, PDF will faithfully reproduce every character, color and image of the manuscript.

Portable document format is an electronic file format. This file format has nothing to do with the operating system platform, that is, PDF files are common in Windows, Unix and Apple's Mac OS operating systems. This feature makes it an ideal document format for electronic document distribution and digital information dissemination on the Internet. More and more e-books, product descriptions, company announcements, online materials and emails are using PDF files.

The purpose of designing PDF file format by Adobe Company is to support the release and publication of cross-platform multimedia integrated information, especially for the release of network information. In order to achieve this goal, PDF has many incomparable advantages over other electronic document formats.

PDF file format can encapsulate text, font, format, color, graphics and images in one file independent of device and resolution. Format files can also contain hypertext links, sounds, dynamic images and other electronic information, support super-long files, and are highly integrated, safe and reliable.

For ordinary readers, e-books made of PDF have the texture and reading effect of paper books, which can vividly show the original appearance of the original book, and the display size can be adjusted at will, providing readers with personalized reading methods.