What is the difference between Stock In/Out and Purchase & Sales?

• Stock In : Select the receiving product in the list and it will immediate adjust in the inventory.
• Stock out : Selects the product being sold or shipped and immediate adjusts in the inventory.
• Purchase : Check the status of receiving products until completion [+New Purchase Order > Order Sent > Order Confirmed > Stock in Closed]
• Sales : Check the status of outgoing products until completion [+New Sales Order > Sold Checked > Stock Out Closed]