I will assume the invoice in on Sheet1 (name does not matter) and take up just one page when printed
Open Sheet2 and add a textbox with you conditions - these could be copied from an existing Word doc if you have one.
We will assume for now there are no other worksheets
See screenshot 1 for silly example. Play with the Term sheet to make the print area only include the text box and in PageLayout unclick Gridlines from View and Print
Open Print dialog: ensure you are set to print on both sides of the paper (duplicate printing) and that you have told Excel to print the entire workbook.
If there are more worksheet and you just want to print two: click on the tab of the first, hold Shift and click the second (this is called grouping). Now in print dialog the first setting should be Print Active Sheets.
best wishes