Go to: Settings > Addresses > Configure
Enter the name that you want to display as sender by filling in the field: Display name
The name you enter above is what recipient will see when they get an email from you
Configure sender name by aliases (addresses)
If you have set aliases (addresses), select the email address you want to configure and fill out the field Display name. That way you can have a unique name for each address. The setting is only applied to the e-mail address you have selected.