Purchase invoice amount and Purchase order amount is not the same

Is it possible to post the invoice amount that Purchase order amount and invoice amount is different ? For example, in case of the price change.

or we have to go back and edit the purchase line ??

yes, you can do it usually.

However, if Invoice matching is enabled in your company, then you might not be able to, depends on the Invoice matching settingsā€¦

How to change the invoice quantity ? We change directly in product line amount in the invoice page ???

How to change the invoice amount ? We change directly in product line amount in the invoice page ???

yes, change it when you are Invoicing the PO. So that, later you can have the data available, if you are interested to know what was the agreed price and what is the price Invoiced.