Dear,

I have made a sales invoice and forgot to include the freight charges. Now, how can I include the freight charges as invoice has already been printed? Is their a possibility to to include it and have a reprint?

Invoice has already been printed means you have created Invoice already so,there is no choice to include the Freight Charges in Invoice .So,you need cancel Billing in VF11,reverse PGI in VL09 and maintain manual Condition Type as Friegh related in Sales Order Condition Tab when you had that Condition Type in your Pricing Procedure ( PP ) only .If not had PP that condition type then you need to insert that condition type and make it as manually check mark .

Also, client has sent a PO for airfreight charges ONLY as it was note mentioned in the previous PO. Is it possible to create an invoice for the freight charges alone? How?

Please have a look into below thread .

http://scn.sap.com/thread/1142486

Thanks,

Naren