You can invite bulk users to all or some selective projects, who have same User Role.

• Go to Navigation Menu Settings > Projects and Users > Invite Users
• Add user email and select all or selective projects from drop down and Invite Users

If you want to add users who have different User Roles then:

• Go to “Administration > Users > Manage Users > Create Bulk Users

Note: Bulk Action to add users to multiple projects is only provided while inviting new users.