How do you show units in an invoice?

To show units in an invoice, clearly itemize each product or service in a separate line with a description, quantity, unit price, and total amount for that item. Ensure that the quantity column reflects the number of units sold, and the unit price is displayed next to it. Additionally, include a subtotal for the items and a total amount due at the bottom of the invoice. This format provides clarity and transparency for both the seller and the buyer.