How to protect email attachments (PDF files) from changing, copying, form field filling-in or signing?

1. Launch the program and select Microsoft Excel file with e-mail address list;

2. Add attachments to the list, PDF files or other format files like Word and PPT;

3. Define "Subject" and "Email Body";

4. Click "Setting" button and select "Security", then you can define security options: require a password to open file, printing, copying or modifying;

5. Click "OK" and then batch send e-mails.