PDF documents have now become a tool that people often use in their daily work. It may be a little awkward to use at first. Once used, you will find that it really brings a lot of convenience to your daily work. Don't be afraid if you don't know how to use it. Today, the editor will sh

Watermark refers to a text or image that covers the content of the article in the file. It can prevent other people's own document content from being copied or forged by others. Now many friends want to add watermarks to pdf documents to improve document security. So how to add waterma