We have built a PO approval Workflow other than the Epicor PO Approval work flow & also we are using other customize PO Approval screen (UD13) refer to below screen
I have add a Print Preview button in this screen. On this button click, how to see the print preview of standard report as used in Purchase Order Entry form.
Note: In purchase order you can print report only when PO is approved. How to see print preview before PO approve.
You have to put more context into a question. We do not know what you are trying to do. What button are you talking about? Where is the button? What have you tried so far.
I agree with @Banderson, the more you put into the question, the more you will get out. If I had to guess, you can trace the button click of a working print preview PO and then duplicate those actions in code.
Put something like the below on a button click event. Two data directives. One in transaction which enables a standard directive and undoes your checkbox. The standard directive does an auto-print of a PO. You need to have the PO number somewhere on the form so you can reference in the auto print.