As you can see in the above image, we have created a purchase order for two items.

Once a receipts is create we can validate the transfer.

After validating we can click on create invoice button as seen in above image.

You can see automatically a vendor bill is generated against that transfer.

In purchase billed qty gets updated and vendor bill count gets updated respectively.

Similarly we have sales order created for two items.

Once delivery is created and validated you can see create invoice button and click for generating invoice.

Automatically an invoice gets generated with all the specific details.

Also in sales order the invoiced qty gets updated respectively.