It has been many years since I have had to do this. I will be sending a pre-publication book reservation form to more than 500 who have indicated interest in my forthcoming book. Some may no longer be interested and others may want multiple copies. So... I will create a fillable form that I will email to the list. Respondents will return the completed form by email. Can I batch-process those PDFs which will all have the same filename and could come in in large numbers at a time? I will use the resulting spreadsheet to bath-generate PayPal invoices.
One way to do this is with the "Merge data files into spreadsheet" option. Which is on the "More" menu in Prepare Forms. This does not append data to an Excel file. It merges all the PDFs into CSV file, which you can import into Excel.