Add users at the account level to give them access to multiple projects. You'll need Account Owner or admin access level to add users.
Logikcull Learning training video:
Step by step instructions:
1. Go to "My Account" tab.
2. Select "Users"
3. Click on "Create New User"
4. Enter the new users email address and email domain.
5. Add users to multiple projects and select their access level by clicking on "Edit User Permissions"
6. Click "Create User"