Forwarding with attachments
Go to the message view (hit "v"). If you want to forward only one attachment, go select it and hit "f". If you want to forward multiple attachments, tag all of them with "t" and then use ";f" to forward them all. Note that if you want to include the message body, then you have to explicitly tag it.
Alternatively, add to .muttrc
set mime_forward=ask-yes set mime_forward_rest=ask-yes