My products / product settings / invoicing module / Invoice settings
The email address from which your customers see the invoices.
Account number on invoice
The account number that your customers can see is on the invoice sent.
BCC e-mail address
When sending billing emails you can have yourself send a copy
Next invoice no.
The system will create the following invoices from this number. However, you can only increase the number with this. So you cannot specify a number that is lower than your highest invoice number.