In some instances wherein repeated attempts to send a user their registration link do not work, or if the workspace administrators prefer to have more control over the credentials of the users, there is a way to set up a user's credentials without them having to go through the usual email registration link.
1. Go to the workspace Admin Tab > Users page.
2. In the Add Users box, enter the email address for the user and select their role.
3. Click on Set Details.
a. IF THE USER WILL BE USING SSO FOR ACCOUNT AUTHENTICATION: Ensure that the box next to SSO Authenticated is checked, and fill in the user information as follows:
b. IF THE USER WILL NOT BE USING SSO AUTHENTICATION AND WILL REQUIRE A PASSWORD: Ensure that the box next to SSO Authenticated is unchecked. This will automatically change the user information options as follows, and allows administrators to enter a Password and Memorable Word for the new user: 
Please ensure that the password and memorable word are stored in a safe place and sent/emailed to the user so that they can log in. The user can always change their credentials once they have logged in to Opus 2.
4. Click on the box next to Send email notification if you wish for the user to be notified by email that they have been added to the workspace.
5. Once all blanks are filled in, click on Create Account. The user will now be added to the workspace and they can log in using the credentials you have set.
BEST PRACTICE:
As a further sanity check, System Administrators can verify on the System Admin page > Users tab that the account is set up with Opus 2 Authentication and that it is a member of the workspace it was added to.