Your username for Salesforce does not have to be your email address

If you are an end user

A user's username and email address do not have to be the same, but it has to be unique because Salesforce does not allow duplicate usernames. For more, please review Error 'Duplicate Username' when you create a username.

The username must be in the form of an email address (i.e. xxxx@xxx.com), but does not have to be a valid email address. To change your username or email, please follow these steps:
 

Note: Be sure the email address associated with your User is a valid email as the email address is used to notify the User of new passwords and other important information.

 

If you are a system administrator

User will receive an email verification to confirm the change of email address.


See also
Guidelines for Adding Users
Considerations for Editing Users

• Click Edit to change your email address
• Click Save.
  • Username can only be changed under Advanced User Details, not Personal Information
  1. Navigate to Setup | Manage Users | Users
  2. Click your name.
  3. Click Edit.
  4. Make changes to the email address.
  5. Click Save.
  6. You will receive the following message: 
  7. Click OK.