To delete an invoice in the "MyInvoices & Estimates Deluxe" program for Windows, you can typically navigate to the "Invoices" section, locate the specific invoice you want to delete, and then use the available options to delete it. After deleting the invoice, you can proceed to the "Estimates" section to work on creating estimates. If you encounter any specific issues or error messages while trying to delete information, it would be helpful to contact customer support for further assistance.