Gmail allows you to setup an alias to send mail out from a different from address. https://support.google.com/mail/answer/22370?hl=en https://support.google.co

Gmail allows you to setup an alias to send mail out from a different from address. https://support.google.com/mail/answer/22370?hl=en https://support.google.com/mail/answer/22370?hl=en Reporting them is more difficult. If it's a known/legit company that is sending the spam like Target or Sears for example, usually you can forward the message with headers to abuse@domain.com. You can also look in the headers for a complaint address. Next you can look for who the provider is that the domain is using and send the complaint to them. If its a fly by night spammer, there isn't too much you can do.