No, your friend will need to enter your referral code when they sign up. However, like another commentor suggested, your friend can speak to the moderators to add the referral.
You can choose which emails you receive by clicking on your avatar in the upper right corner —> select ‘My settings’ in the drop-down list —> select ‘Subscriptions & Notifications’ —> click on ‘Notification Settings’ to view your general setting and ...