Notes can be added to Purchase orders when you are either creating the purchase order, or can be added at a later time when editing the purchase order.
To create a new Purchase Order, go to Accounts > New Purchase.
To edit an existing Purchase Order, go to Accounts > Purchases > select the edit pen for the Purchase Order.
In the opened purchase order, scroll down to the Notes section. You can add your notes here, and then select Save then Close, or Save & New. As indicated at the top of the notes section, these notes will appear in the Purchase Order PDF.
