In the process of editing PDF documents, if you need to make a short comment on a long document; fill in or sign a form or agreement, and return it by email; proofread, review and correct a document right on your screen; make some notes or drawings right on the pages; illustrate your ideas or suggestions; grade student papers right on your PC, laptop or Tablet PC, and so on. In cases like these, you need a tool like PDF Annotator.

Power-user is a top-level productivity add-on for Microsoft PowerPoint and Excel, developed by Power-user SAS from France. It can help users quickly create and edit PowerPoint and Excel files, so as to increase their productivity by as much as 40 percent, reduce the amount of time required to work and dramatically increase the work efficiency.

There are so many high-quality videos on YouTube that are worthy of downloading for collection or need to be downloaded for enjoyment later due to poor Internet connection speed. There are usually 4 approaches to do this:

1. Online tools: it's efficient and simple, without downloading and installing; but their function is simplex, and only supports a few resolutions;
2. Browser plug-ins: it has similar pros and cons with the former;
3. Desktop software: it requires downloading and installing software, with relatively powerful functions;
4. Command lines: very powerful, but requires some prior configurations, and difficult for beginners to use.

In some cases, we need to remove the background of the main character in a photo (that is, separate the wanted object from the photo), then use it for many other purposes. Examples include uploading product images to eBay, preparing photos for a job hunting or online dating website, placing it in other backgrounds, creating photo collages, etc. For similar needs, almost all of us know that Adobe Photoshop is specially designed to do just that. But most people don't want to learn it for this unless they are doing it for a living.

PDF-XChange Editor is a PDF reading and editing tool, once known as the smallest (now also becomes a bloated application), fastest and most feature-rich PDF document reader + editor. It focuses on the editing functions of PDF type of electronic documents, and supports many PDF file related editing functionalities such as creating, viewing, editing, annotation, OCR recognition and digital signature.