You can input multiple email addresses in the E-mail field with semicolon as the separating character. Here are the steps:
1. Open the form in Foxit PhantomPDF
2. Choose Home > Select Annotation
3. Double click on the form field you want to add ‘submit email’ action.
4. In the pop-up field Properties dialog box, choose Action, click on the arrow icon on the right side of the Select Action, choose Submit a form, and click on Add button.
5. In the Submit a Form panel, input E-mail addresses, use the semicolon to separate the email addresses like email@example.com;firstname.lastname@example.org
6. Click on Ok to apply the setting.