Module to do something after Invoice PDF is created

I was reading that Dolibarr is using Hooks and Triggers a module can use. I installed Module Builder on my playground setup and want to run a file-copy of the invoice PDF after it was created.

I already added this archive feature into send recurring invoices by mail, which works great. But I miss the manually created invoices in the archive. So I am looking for a way to run this copy as module after the validated invoice is created as pdf.

I found 3 triggers in the source

$result = $this->call_trigger(‘BILL_VALIDATE’, $user);
$result = $facturerec->call_trigger(‘BILLREC_CREATEBILL’, $user);
$result = $this->call_trigger(‘BILL_CREATE’, $user);

but I am very new to Dolibarr, so I am not 100% sure which trigger or hook should be used by my module.

Any hint would be greatly appreciated.

Thank you