Whenever you are sending emails from offers, you can choose the account from which you can send the email. By default. 'Default' email account is selected.
If you want to use an account in PegaMKT-Work class , you need to create and configure it.
To configure a new account in your class, you can use Email Wizard.(Configure>>Integration>> Email>> Email Wizard )
Or you can go to RecordsExplorer>> Integration-Resources>>Email Account and create new.