https://support.google.com/mail/answer/10957?hl=en
Turn on automatic forwarding
- On your computer, open Gmail using the account you want to forward messages from. You can only forward messages for a single Gmail address, and not an email group or alias.
- In the top right, click Settings .
- Click Settings.
- Click the Forwarding and POP/IMAP tab.
- In the "Forwarding" section, click Add a forwarding address.
- Enter the email address you want to forward messages to.
- Click Next Proceed OK.
- A verification message will be sent to that address. Click the verification link in that message.
- Go back to the settings page for the Gmail account you want to forward messages from, and refresh your browser.
- Click the Forwarding and POP/IMAP tab.
- In the "Forwarding" section, select Forward a copy of incoming mail to.
- Choose what you want to happen with the Gmail copy of your emails. We recommend Keep Gmail's copy in the Inbox.
- At the bottom of the page, click Save Changes.