I am always on the lookout for free ways to work with PDF documents. DocHub is not a new program, however they have reached a point where this is a great all around tool. Not only can you now edit PDF document (it is super easy!), now you can actually highlight, sign, markup, insert images and it is linked to your Google Drive. To be honest I can not believe this app is free. It does so many things that where typically you would need multiple apps to help now you only need DocHub!