Add users (persons / contacts) from General --> Users section
1.) Select General --> Users and then click the "Add new user" button on the tab that opens
2.) when you add a new user, you need to choose user type :
- Contact, if the person should not be able to log into the system
- System user, if the person should be able to log into the system
3.) If you choose, "System user" type, you also need to select user group. If you choose "Support user" then these are free of charge and can only log in through the support center portal.
4.) To be able to select a user as reporter or owner an issue/task you also need to add that user to one or more projects/workspaces in the project/workspace access tab.
Add users from issue / tickets
1.) Open or create a new issue
2.) On the right of the reporter field click on the icon
3.) In the popup that opens fill in the information below and then click save.
The user created will be added in the system and also to the project/workspace automatically. Also, the user is a contact by default, i.e. a free user without any permissions to log in. If you choose "Support user" then the user will be a "Support user" that is also free and can only log in through the support center portal if you send him/her a password
More on user management is available here..