It is useful to occasionally change the passwords on your e-mail accounts to maximize your e-mail security. You should always change your password if you think someone else has access to your account.
Note: Make sure that you change the password in your offline e-mail application as well, or you will not be able to upload or download e-mail to this account.
To change the password of an e-mail account:
Click on the Add/Remove Accounts link in the Mail area.
Click on the Change Password button next to the required e-mail address.
Enter the new password in the New Password field.
Click on the Change button. Your password has now been changed for that account.