What is the diff between proforma invoice & actual sales invoice If their is no difference then which invoice no. customer will record in his book?

Pro Forma Invoice: This Pro-forma invoice is one which is sent before the commercial Invoice(original invoice) to receive advance payment from buyer. The seller will not record this as 'Account Receivable' in his account and buyer will not record it as 'Accounts Payable'in his account. This is not true invoice.Invoice" This is true invoice where in the seller and buyer will record in their 'Accounts Receivable section' and 'Accounts Payable Section'. Payment will be done once the invoice is received by the buyer . 

Proforma Invoice is like a quotation which will be received from the supplier for procuring the material. But actual Commercial Invoice or Tax Invoice will be sent by the supplier along with material.

As per my knowledge, customer has to record the Commercial Invoice along with the proforma invoice and the purchase order for future audit reference.

Thank you..