When creating a form we recommend setting a reply email address. Otherwise, when a person receives email confirmation after submitting a form, it is sent from firstname.lastname@example.org. If they then try to reply to their confirmation email e.g. they have made a mistake on the form, it will not be received by anyone.
To add a reply email address follow these steps:
Go to Dashboard > Online Registrations > Edit (pencil icon) of that Form (see How to edit a form).
Enter an email address into the 'From' email field. This is a required field where you enter the email address in which registrants are able to reply to their form confirmation emails to. This field will often already be pre-filled with the email address of the person who created the form however, you can change this to another email address.
Click Save Form.