Normally, emails sent from your store will be shown to the recipients as coming from the full email address (i.e., firstname.lastname@example.org).
However, it is possible to change the email format to use a display name alongside the email address. To do this, just enter your email address in the Online Store Manager fields (store settings, email templates) in the following format:
Display Name <email@example.com>
Be sure to include the email address within the angle brackets as shown above. When the emails are received, they will include the Display Name along with the email address in the recipient's email client "From" field.
However, it will not work on the Newsletter or Autoresponder email settings found in your Marketing section. These emails will be pre-formatted with your @domain designation and cannot be edited this way.