To add new users to your Insightly account, you should be a system administrator. If you created your Insightly account via Google Apps, you may add your users directly into Insightly. In case, you signed in Insightly account without Google Apps or want to add new users from another domain, you need to send them emails with an invitation to register.
When you use a paid subscription, the additional users will increase your monthly fee. You can see the existing level on your System Settings in the Billing & Account.
To add a new user go to your icon in the right upper corner of your page layout, and then to System Settings and choose User list.
Click on the ‘Add New User' button to add or invite new users.