Google will soon roll out invites for their Inbox email app to some Google Apps customers. First launched in October 2014, Inbox is a new, Gmail-based take on email management. The roll out begins in March, with Google choosing a select few companies for the early adopter program at first, wanting to work with each business closely.
To start, we plan to work very closely with the early adopter companies, so not everyone that applies will be accepted right away, but the program will continue to expand over the coming months.
To sign up, a Google Apps administrator must apply for entry into the early adopter program at firstname.lastname@example.org.
Source: Google for Work blog