The user access is quite straightforward, the user are linked to a personal email for regulatory purposes (electronic signature compliance with Part 11 and such). R/W users (can be admin or not) to at least one project will need a license, Read-Only are unlimited and for free.
Example: if you have USER A, B and C as Read/Write access and USER D and E as Read-only:
User A, B and C can change everything they want (in the selected project they have access to)
User D and E can read, download document and even sign documents. These two users are for free and you pay for 3 licenses.
As guest option you can invite any external user by creating an account and having her/him as Read-Only (like an auditor). It’s for free but he won’t be able to fill in test forms or comment some reviews (for that (s)he needs editing rights). See How can I give external people access to my project?
But, what you can always do is this: during a test period where USER D and E need to be involved, you can adapt the access and put:
User A, D and E with R/W access
User B and C you change them to Read-Only access so that the monthly invoice is not changing (you still pay for 3 licenses).
So, in short:
Admin and R/W user to at least one project will pay a license (admin will have access to the administration part of the SW to configure, manage users etc.. no extra cost for that)
Read-Only users are unlimited and for free (can read, download and sign documents)
For QMS project, there is another access, it’s the Q access. This access is for free but even more limited than the Read-Only access as it provides access to the published QMS only (LiveQMS platform) without providing access to the Matrix project at all. Very good for an external auditor for example.
PS: if you want to restrict the R/W access for some users allowing them to only edit certain part of the project (only the TC and execution, not the other design element for example), you can use an extra module called User access limitations. This module allow you to specifically provide write restrictions for group of user(s) within a project. More info https://docs.matrixreq.com/administration-and-configuration-guide/project-settings/user-access-limitations/
If you’re using group of users, you can also manage the access to different project with the group of users (to be more efficient than doing it per user). The highest access provided via the group or the single user will determine the final access to the project. More info on Group Access to Projects .