It has been a while since I had to deal with this. I use Gmail and find that I don't much worry about account settings anymore.
My recollection is that one would set up an exchange account. I recall that configuring it for "IMAP" rather than "POP3" tended to result in better synchronization between phone and server. I always had to use a web search to find the proper IMAP settings for my EMail service. I suspect most services support both.
My gmail acct works fine, but also need to use this web email as only a POP3. Unfortunately, with Nexus 5 I have to remember to manually BC myself each time I send - no automatic setting in the phone that I can find.
Sent from my Nexus 5 using AC Forums mobile app
If I'm understanding your question correctly, the prior reply about setting up the account using an imap server is correct (although there's nothing about exchange accounts to worry about if you're using the non-gmail e-mail app that comes stock on the phone). You should contact your e-mail provider to find out what the correct server settings are for using your e-mail address over imap. The advantage that imap has over pop3 is that the e-mail messages will sync in real time with your e-mail providers servers. In that way, messages read in your inbox on the phone show up read in a web browser on a computer, messages sent from your phone show up in the sent folder in a web browser on your computer, messages deleted from your phone show up in the trash in your web browser on the computer, etc. If you can advise who your e-mail service provider is, the settings you need are likely to be easily found via a Google search. Hopefully this reply helps to clarify. If you can post back who your e-mail provider is, I'll be glad to see if I can find the correct server settings for you.
I am not sure, even, that sending blind courtesy copies to yourself (same EMail account) will solve your problem. I assume that these copies would also be quickly downloaded by the phone and removed from the servers. I suppose you could test this by sending a message to yourself with the stock app. Does it show up on the server once your phone has it?
Have you checked other mail apps? Perhaps they have the BC address field you are looking for.