Each license is individual, and it isn't recommended that it be used across multiple devices at the same time, as that can cause errors in synching your content. If you wanted to use Atticus on your desktop during the day, and move onto your laptop for the evening or during travel, that wouldn't be a problem because it would only be live on one device at a time.
If you do choose to give a co-author or another team member access, they will have to use your email and password to access your account. In these cases, we strongly recommend you coordinate schedules to be sure you're not both working in Atticus at the same time. You will also each need to fully log out of Atticus using the profile icon in the top right before the other person accesses the account.
I also encourage you to check out our Terms & Conditions, particularly section 5, to explain the licensing terms in more detail: https://www.atticus.io/terms-conditions/