Creating the year-end donor letter for contributors has always been a challenge for small non-profits using QuickBooks. There just has been no easy way to do...
You can add multiple customers with QuickBooks->Import->Contacts. You probably want the "Paste from spreadsheet or enter manually" option.
There is no provision in Quickbooks Mac 2019 for editing multiple existing contacts other than doing it individually (there is a provision for editing 1099 information for vendors en masse)
