I just tested this on my iPhone and it worked just fine. I purposely sent it to my Gmail account, just to be sure that wasn't part of your problem. Now as far as the Sent folder is concerned, the mail sent in that method (share) would be sent by your default account in Mail. For me, that is my Comcast account. I checked in the Sent folder there and it was there. If you go to Settings>Apps>Mail>Default Mail App, what do you see there? If you scroll down the mail settings area a little further under Composing, what is your Default Account? If you check that account in Mail, is it in that Sent folder? If not, do you see an Outbox with a mail in it? If you do, that would indicate there is a problem sending from that account.