A) Go to  Woocommerce-> Settings -> RAE setting-> Exchange Products-> Enable “Enable Exchange Request.” -> After that you have to select Maximum Number of Days.If value is 0 or blank then Exchange button will not be visible on order detail page. And Select the order status in which the order can be Refunded.

Do the same process for showing Refund button.    

Go to Plugin's  refund setting->go to select order statuses which the order can be refunded setting -> select order statuses from the drop down at which you want to show refund button and do the same process for showing exchange button.