iAnnotate

iAnnotate is a useful application for Android with which you can take notes and write on any PDF file you have saved on your device, using a wide range of colors and writing options. Thanks to this app, it's easier to take notes in class, or clarify a point on an important work document.

This application offers four editing options: freehand writing, underlining and crossing, text, and notes. You can use the first one to draw anything with your fingers, which is great to make visual notes like circles and arrows of any width. The underlining and crossing let you draw a line beneath a sentence or on top of it, no matter how long it is. Text and notes are similar but have specific characteristics: text lets you write in any direction, while notes create a watermark where you have to click to open and read the note you make.

All these features can help you be clear in every paragraph, and make sure yourself and others understand the text. When you're done editing the PDF you can share it with your contacts using your email, or you can open it using any reading app you have installed.

iAnnotate is, without a doubt, a good application to work with this type of files, which can't be modified with any common text editor.