secondly email for booking confirmation

Is there space for you to enter 2 emails?  If not presumably no. Can you put an Auto Forward on one email account so automatically goes through to second? Sounds like the easiest and you can set that up for specific words, etc, so only from booking.com gets forwarded.

Hi

Yes you can, top right circle menus, first one, is contacts.

In there you can define roles and email.

Kind regards