With Imonggo, you don't directly change the item quantity. Instead, you record a transaction that will either increase or decrease the quantity.
Go to Stockroom -> Transactions and follow the steps below.
To increase inventory, you can use "Receive from Supplier" or "Adjustment In".
To decrease inventory, you can use "Return to Supplier" or "Adjustment out".
You can also use "Physical Count" to adjust the quantity of items to a specific count.
A "Sales Invoice" transaction at the Store will automatically decrease the quantity of the item sold.