On the babelforce manager app under Global settings > user management you will find an overview of all users and the roles assigned to each of them. There, you can easily add and remove roles with the exception of the role agent. (Agents can only be added and removed via the agent or integration section.)
To add new roles just click on the Add button on the top right hand side, then enter the User(email) choose what role will be given to the user, choose a password and save. To learn about each of the roles take a look at this article https://help.babelforce.com/hc/en-us/articles/360052733892-babelforce-Manager-User-Rights-Management
To remove a user you simply click on the little trash can on the left side and the user will be removed.
If needed, you can also change a user's role or add another role by clicking on the dropdown menu and choosing from the options available.