One feature Gmail lacks is the ability to automatically forward outgoing messages to another email address. This means that if you want to save your sent mail on another account for any reason, you have to forward each message individually. To implement automatic forwarding of sent mail, you must install a browser add-on or use a desktop mail client, although each option has its limitations.
Firefox and Chrome Add-Ons
If you use either Chrome or Firefox, you can install a browser extension that automatically forwards your sent Gmail messages. The downside to this approach is that you have to install the extension on each computer you use, and also use the same browser. Two extension are available for Chrome: Bcc Me for Gmail and Auto BCC Gmail (links in Resources). If you use Firefox, you can install the Greasemonkey add-on, and then run the GmailAutoBcc script (links in Resources).
Use Outlook or Thunderbird
Another way to automatically forward your sent mail is to use a desktop email client such as Microsoft Outlook or Mozilla Thunderbird to send your messages. You must first add your Gmail account to the desktop client, and then configure the client to autoforward any messages you send from the Gmail account. This method requires that you send all your messages from the desktop application instead of from the Gmail site.
Manual Forwarding
If none of these options appeal to you, you can still forward your sent messages one at a time from your Sent Mail folder in Gmail. However, this adds extra header information to the forwarded messages, often making them harder to read. To eliminate the extra header information, forward the messages at the same time you send them by adding the forwarding address into the messages' BCC field. The forwarding address remains hidden from the other recipients.
Filter Limitations
Gmail's filters are designed for incoming messages, which means that while you can create a filter that forwards messages you receive in your inbox, you can't automatically forward outgoing messages using a filter.
Firefox and Chrome Add-Ons
If you use either Chrome or Firefox, you can install a browser extension that automatically forwards your sent Gmail messages. The downside to this approach is that you have to install the extension on each computer you use, and also use the same browser. Two extension are available for Chrome: Bcc Me for Gmail and Auto BCC Gmail (links in Resources). If you use Firefox, you can install the Greasemonkey add-on, and then run the GmailAutoBcc script (links in Resources).
Use Outlook or Thunderbird
Another way to automatically forward your sent mail is to use a desktop email client such as Microsoft Outlook or Mozilla Thunderbird to send your messages. You must first add your Gmail account to the desktop client, and then configure the client to autoforward any messages you send from the Gmail account. This method requires that you send all your messages from the desktop application instead of from the Gmail site.
Manual Forwarding
If none of these options appeal to you, you can still forward your sent messages one at a time from your Sent Mail folder in Gmail. However, this adds extra header information to the forwarded messages, often making them harder to read. To eliminate the extra header information, forward the messages at the same time you send them by adding the forwarding address into the messages' BCC field. The forwarding address remains hidden from the other recipients.
Filter Limitations
Gmail's filters are designed for incoming messages, which means that while you can create a filter that forwards messages you receive in your inbox, you can't automatically forward outgoing messages using a filter.