The primary function of user authentication is to verify the identity of a user attempting to access a system or service. This process ensures that only authorized individuals can access sensitive information or perform specific actions within an organization. User authentication typically involves validating credentials, such as usernames and passwords, and may include additional layers of security, like two-factor authentication (2FA) or biometric verification. By implementing robust authentication mechanisms, organizations can significantly reduce the risk of unauthorized access, data breaches, and security threats.