Hurdlr offers two formats for reports: PDF or spreadsheet. Most reports like your Business Mileage by Business or your Business Expenses by Business will be exported in PDF format.
If you would like to export your reports in spreadsheet format to open in Excel or other spreadsheet programs, you will have to select a report that has (Spreadsheet) next to the title like the Expense Detail List with Receipts (Spreadsheet) report. There is a spreadsheet version in each section (Income, Expense, Mileage, etc).
You can export your reports by following the steps here.