'Send me a copy of invoice' is a flag that lets invoice owners receive a copy of the invoice and outstanding invoice email. This option is available when emailing invoices to customers. When the flag is checked, the invoice owner will receive a copy of the invoice and email reminders. 
 
The default value of 'Send me a copy of invoice' is controlled by the 'Email me a copy of invoice' flag in the Payment Center Settings. For instance, if  'Email me a copy of invoice' is checked in the settings, when you send an invoice, the default value of 'Send me a copy of invoice' flag is set to true. If 'Email me a copy of invoice' is unchecked, the default value of 'Send me a copy of invoice' flag is set to false.
'Email me a copy of invoice'  is enabled by default upon the initial installation of Payment Center.
 
Furthermore, 'Email me a copy of invoice' also applies when sending invoices by batch and during Auto-Billpay. If the flag is checked, the invoice owner will receive a copy of the invoices and reminders. Otherwise, if unchecked, the invoice owner will not be copied in the emails.
To disable the setting, simply uncheck 'Email me a copy of invoice' flag.
 
Please note that for existing Recurring Invoice and Invoice records, 'Email me a copy of invoice' should be unchecked.