What is the difference between Purchase Order and Invoice?

There are some people who are a bit confused with the differences between Purchase Order and Invoice. The purchase order is something that people use in order to buy some items from the seller. This can be sent before the invoice. Invoice is sent by the seller to the buyer to let the buyer know that the payment is due soon. Take note that the invoice will include different details about the order.

It will place the date of delivery, the invoice number, and the PO number. This will let the buyer know when the order will arrive and will be received by the buyer. If buyers would not sell the money, sellers should not ship out.