Earlier quoted context omitted.
From a GDPR perspective,sending an email gives the recipient the implicit permission to store and read the contents and metadata of the email, but not to transfer it to other parties (except the data processors that process the email) or publish it.
Does that mean I'm not allowed to forward emails you send me?
My guess is that forwarding would be fine but publishing wouldn't (in the US) and that you as an end user don't have to worry about the GPDR.