To change the email addresses you need to go to the "Contact Details" page of your website. Login to the editor and then go to the "email addresses" section. You can then change the appropriate field to the email address you wish to use. Once you have done this simply save your changes and close the editor. The respective forms will then go to the email addresses you set.
If you wish to add multiple email addresses then simply separate the addresses with a semi-colon (;)
You can view how to do this in the short video below