A purchase invoice is an itemized statement of the goods or services provided by a vendor or supplier. It indicates the quantity and price of each product or service provided or to be provided.
Normally the "finance" team is in charge of managing this stage of the chain, which usually comes after "Goods Receipts" booking and management.
Suppliers could send the corresponding purchase invoice/s together with the delivery note/s attached to the goods, that implies that a "Purchase Invoices" can been automatically generated
from the "Goods Receipt" window, but it could be that is not the case, therefore a purchase Invoice can also be created from scratch in the "Purchase Invoice" window.
The purchase expenses can be recognized as soon as the purchase invoice is accounted, however if an expense deferred plan is configured it is possible to deferred the expense recognition as required.