Enter the verbiage you wish to appear in the Terms & Conditions large text box.
Add the text you wish to appear in the footer for the invoice.
Provide a name of the template.
Click Save as New.
Verify that your template dropdown box matches the new template you just created.
Go to Sales > Sales Ordersand open a new invoice. You will notice the Terms & Conditions field under the pricing table and the footer reflect your template.