Which must be unique for each user in the cloud service?

In cloud services, particularly in systems like Profitability and Cost Management Cloud (PCMCS), the requirement for unique identifiers is essential for user management and security. An email address is often used as a unique identifier because it functions as a primary means of communication and account recovery for each user. Since email addresses must be unique to ensure that communications are directed to the correct user, having each email address distinct prevents issues such as confusion in login credentials or account recovery processes.

In contrast, while user names, passwords, and names can also have unique attributes, they do not necessarily need to be unique in the same way that email addresses do. Multiple users can often share the same first and last name, and although user names should ideally be unique, systems might accommodate similar names with variations. Passwords, however, are intended to maintain the integrity of an account but do not serve as identifiers across the platform. Therefore, the email address stands out as the required unique element for each user.