When you create an order it is possible to customize the date of the order. If you do not change the order date, it will automatically default to the date you are creating the order.
To change the order date, you will first need to place the order and hit Accept. Once the order is in Accepted Status, select the pencil icon beside the date and then toggle it to the new date (which can be either a previous date or a future date).

Once in Accepted status, you can change the date of an order in any status, except Posted Status. If the date has to be changed once an order is in Posted Status, you can Unpost the order and edit the date.
To refresh the date within the Doc 60, select Regenerate Invoice found under the three dots.

VIDEO: How to Change an Order's P.O. Number, Reference Number & Date