Boxes are the package format for Vagrant environments. A box can be used by anyone on any platform that Vagrant supports to bring up an identical working environment.
vagrant box utility provides all the functionality for managing boxes. You can read the documentation on the vagrant box command for more information.
The easiest way to use a box is to add a box from the publicly available catalog of Vagrant boxes. You can also add and share your own customized boxes on this website.
Boxes also support versioning so that members of your team using Vagrant can update the underlying box easily, and the people who create boxes can push fixes and communicate these fixes efficiently.
You can learn all about boxes by reading this page as well as the sub-pages in the navigation to the left.
The easiest way to find boxes is to look on the public Vagrant box catalog for a box matching your use case. The catalog contains most major operating systems as bases, as well as specialized boxes to get you up and running quickly with LAMP stacks, Ruby, Python, etc.
The boxes on the public catalog work with many different providers. Whether you're using Vagrant with VirtualBox, VMware, AWS, etc. you should be able to find a box you need.
Adding a box from the catalog is very easy. Each box shows you instructions with how to add it, but they all follow the same format:
$ vagrant box add USER/BOX ...
vagrant box add hashicorp/precise64. You can also quickly initialize a Vagrant environment with
vagrant init hashicorp/precise64.