Within Modern Treasury, you can add as many users as needed in order to provide access to payment or banking information.
Users can be added with their full name and email address:
You will want to designate the user's roles for their respective positions and needs. Also, depending on what is required, you can choose to enable a user for roles in both live and test mode or only for one needed mode.
Submitting "Create User" sends the user an email to sign in to Modern Treasury for access.