To put an order on-hold, following these steps:
Step 1: Make sure there is no signing status added to the order. If there is a completion status, you can remove it by clicking on it:
On the window that opens click "Remove signing status."
Step 2: Once the status has been removed, click on the downward facing arrow next to "Send Invoice & Close Order" and on "Order on-hold" in the dropdown menu:
Step 3: The order will then be on-hold until you re-activate it: