One must-have feature (for me) in any mail client is the ability to automatically BCC an address with outgoing mail. I use this to log all my outgoing mail so that
- I can verify that mail was sent, for troubleshooting purposes.
- I can have a record of my correspondence in case I ever need to show that, yes I did send that email I said I sent last week, thankyouverymuch. Having mail in a sent folder on my own system doesn’t really do that — it’d be trivial to edit the mailbox on my own system.
I’ve found that most mail clients support this — but many make it hard to find the option.
In case you’re wondering where to find this in KMail, it’s under Settings -> Configure KMail. Then go to Identities and click the Modify button. It’s under the Advanced Tab, shown here.

Hope that helps!
Thank you! I struggled with this for quite a while… Kmail definitely made it hard to find.