If your e-mail recipients see only part of your name, such as your first name, but you want them to see your full name, you can easily make the desired change. The display may show only part of your name if you did not type your full name when you first set up your e-mail account.
To display your full name, edit your name in Account Settings.
On the Tools menu, click Account Settings.
On the E-mail tab, select your Internet service provider (ISP) account, and then click Change.
Under User Information, in the Your Name box, type your name the way you want it to appear to people who receive e-mail messages from you.
Click Next, and then click Finish.
Note: If you are using a Microsoft Exchange account, you cannot change the display name. Only your Exchange administrator can make this change.