To facilitate collaboration, you can easily invite other people to: 

When you invite another person, you also have the option to select the level of action that your collaborator will have, you can choose between "can view" and "can edit" access rights.

Additionally, you  have the possibility to send unlimited "can view" invitations, even to people without a STRUCINSPECT membership.

In the other hand, "can edit" invitations allows people to actively perform tasks in the Infrastructure Lifecycle Hub. Therefore, a membership is required, and you have to enter the e-mail associated with that person's STRUCINSPECT account, when sending the invitation.