Trello

When it comes to project management apps you can use for free, Trello is at the top of the list. This is a simple but powerful app that you can use on your iPad, iPhone, and pretty much any other device you own. Like Google Docs, anyone can use Trello for free as long as they have an account. 

With Trello, you can create boards for your projects and share them with your coworkers or clients so everyone is up to date with the latest assignments and other relevant information. Moreover, you can customize it and add a bunch of helpful tools to make sure the work gets done. 

Trello offers a premium subscription service, but for most people, the free version has everything they need to get started.