Open the pdf file, switch to the Insert tab, click Watermark, select Delete Watermark pop-up window, and click OK to delete.

PDF file format is a sharing method developed in the early1990s. It can include file format and built-in images, and can be operated across platforms, even though the recipients may not have related or shared application software interfaces on completely different computer platforms.

At that time, those competing with PDF for cross-platform file formats included DjVu (still under development), Envoy, Common Ground Digital Paper, Farallon Replica and Adobe's own PostScript (. Ps) format. In the years before the rise of the World Wide Web and HTML text, PDF was very popular in desktop publishing workflow technology.