Bulk email

Before there was an option to see the full header of an email, how I don’t see it? How to know the IP address of the sender?

The subscribers have been invited, and they have confirmed the invitation. The weird thing is that they received the invitation and confirmation e-mails in their inbox and the posts in the junk mail, of their e-mail accounts. Is there some software or trick to make the posts arrive at the inbox?

is it possible to send an email without showing your email address to the other person?