Aapki privacy policy me specifically explain hona chahiye:

Data processed
SMTP credentials/authentication information
Sender email address
Recipient email addresses
Email subject
Email content/HTML
Campaign information
Unsubscribe information
Purpose
SMTP connection/testing
Email delivery
Campaign processing
Unsubscribe management
Delivery reporting
Retention

Agar sach me credentials/email content permanently save nahi hote, clearly state:

SMTP credentials and email content are processed only as necessary to perform the requested email delivery operation and are not retained after processing.