Salesforce provides each user in your organization with a unique username and password that must be entered each time a user logs in.
As an administrator, you can configure several settings to ensure that your users’ passwords are strong and secure, read more in Password Policies.
One of the main tasks of the Administrator is to ensure all users can access the environment. For this you need to know how to Reset Passwords
When a user loses a password, the user can click the forgot password link on the login page to receive an email with steps to reset a password. The user must correctly answer the security question to reset the password.