A small box will pop up with options like add comments, draw shapes like squares, circles, and lines, highlight text using color, underline or strikeout or simply type your thoughts. With Xodo, annotating and adding comments is as easy as long-tapping anywhere on the page. The reason why Xodo made it to this list is because the UI is not only functional but the app comes with some cool features. PDF Annotator and Marker for Androidįirst up in the list is the Xodo PDF Reader and Editor, which is one of the highest rated, free PDF annotator and marker apps on the Play Store. Whether you are using an Android, iPad, Windows or Mac, we will cover at least one app for each. Instead of using paid PDF editors that offer advanced features that you don’t really need or could care less about, it is better to get a PDF annotator and markup tool that will help you with just that, mark, annotate, and comment.