fromArn

This parameter is used only for sending authorization. It is the ARN of the identity that is associated with the sending authorization policy that permits you to specify a particular "From" address in the header of the raw email.

Instead of using this parameter, you can use the X-header X-SES-FROM-ARN in the raw message of the email. If you use both the FromArn parameter and the corresponding X-header, Amazon SES uses the value of the FromArn parameter.

For information about when to use this parameter, see the description of SendRawEmail in this guide, or see the Amazon SES Developer Guide.