In Organization Wide Address we associate a single email address to a user profile or to all user profile. Each user will use the display name and email address while sending the email with respect to profile.
Setup > Email Administration > Organization-Wide Addresses
Organization-Wide Email Addresses > Add
Display Name: Enter the display name which will appear on outbound emails. Maximum character length is 300
Email Address: Enter the email address and this will be a standard email address.
Select one of the following options
Allow All Profile to Use this from Address
Allow Only Selected Profile to Use the From Address: Select System Administrator