There are additional buttons "Print receipt" and "Export to PDF" available after the payment (You also can print the receipt from the "Order monitor").
When you print a receipt for MO/TO payment, the client's signature field is marked as «MO/TO» (without the quotation marks).
Pressing the "Print receipt" opens a preview window, the "Print" button is in the upper-right corner of the window.
Window for receipt preview