PDF markup and annotation isn't that difficult in and of itself. You can annotate and highlight PDF's using built in applications like Preview on Mac or Adobe reader or Acrobat on Windows. There are also countless third party apps like Drawboard PDF and others that let you markup and annotate PDF's.
For most cases, however, the purpose of annotating and highlighting PDF's is to share it with others and collaborate together.
To do that you need a way to share the PDF easily via an online link and make in-context comments directly on different parts of the PDF. Additionally, you want to make sure other people you are sharing your annotated pdf to DO NOT need to install a new app.
In this post, we'll show you a super simple way to annotate and markup PDFs online—without installing any new pdf annotation tool or app for you or the person you are sharing to.
You can do this via Instacap's online pdf annotation feature.