I had been receiving quite a number of inquiries regarding my video on how to create annotations in PDF.JS. First and foremost, I call my web application Annotationeer. It is built on top of PDF.JS. It has the following annotations: Square fill Square border Circle fill Circle border Stamp Arrow Sticky note Measurement distance (like in Adobe Acrobat tool) Measurement area (like in Adobe Acrobat tool) Audio (in MP3 or OGG) Free hand drawing Free hand text (1 liner) Text Underline Text Highlight Text Strike-through Form fields like text field, checkbox, radio button Digital Signature All annotations come with a comment and properties like background and foreground color, measurement units in inches, centimeter or millimeter and font size to name a few. These same annotations can be accessed through the sidebar as a list where you can scroll through as well as a comments popup window to initiate a chat history for every annotation. Some nifty ...