To copy documents and convert them to another document, for example receipt ,we go Purchases/sales-> list of documents and choose the documents we want to copy.
Then press the magic stick icon and select the type of document we want to be copied.
If we check the date ,our document will take the original date, otherwise the current one.
Also, if we want to convert to a receipt and not just copy the items/products but add an item with the total amount of the document go to settings->documents and to the document to be copied, in the column “Item” we write the ID of the item/product that will contain the total value of the original document that will be copied with the prefix “#” .