You can find the configuration of the e-mail addresses used by your store under System | Configuration | Store Email Addresses. There you will see several sections representing different e-mail senders:
General Contact: By default, this is used to send out general e-mails such as the confirmation e-mail that gets sent out when a customer account is created.
Sales Representative: This sender is used to send out sales-related e-mails such us order confirmations and shipment updates.
Customer Support: This sender sends out e-mails such as password reminders.
Custom Email 1: This is an extra sender that you can use if the distinction between General Contact, Sales Representative, and Customer Support is not enough for you.
Custom Email 2: This is an extra sender that you can use if the distinction between General Contact, Sales Representative, and Customer Support is not enough for you.
After clicking on each section, a form...