Your Userlike invoices will be sent to the owner's email address. Should you wish to download them again, you can do so via the Userlike Dashboard by clicking on "Account", then "Invoices" in the left menu. Please note that this area is only available to the account owner.
Then you can download the corresponding invoice in the list via the download button.
It is possible to add a secondary email address for invoicing. You can update your billing information via the Userlike Dashboard by clicking on "Account", then "Billing" in the left menu. Here you can set additional email addresses.