Inviting and adding users is simple.
Plus, all plans include unlimited users so you're welcome to invite everyone on your team to use Insycle.
Simply share the sign up link https://www.insycle.com/getstarted/ with your colleagues. After they fill it out and login to Insycle they'll join your plan automatically.
Insycle uses Single Sign-On and plans are tied to the underlying app account, that's how Insycle associate users to the right account. For example, for Salesforce, all users that belong to the same org ID are part of the same plan, for HubSpot it works the same way based on the portal ID, etc.
To connect more apps to Insycle check out this article.