The email addresses used as the From and Reply-to addresses depend on the type of email being sent.Email typeFrom addressReply-to addressAutomatic emailsThe From email field on your Organization details screenThe Contact email field on your Organization details screenEvent emailsThe From email field on your Organization details screenThe event organizer which defaults to the Contact email field on your Organization details screenManual emailsThe From email field on your Organization details screenThe Reply to field on the Recipients tab of the email wizard, which defaults to the current administrator's email addressYou can change the Contact email address from your Organization details screen. You can only change the From email field if you are on a paid plan and have a  custom domain  set up.