You can control this setting for the following modules:

Invoice, Proforma Invoice, Sales Receipt, Estimate, Delivery Challan, Purchase Order, Bill, Credit Note, Debit Note.

You can easily enable/disable the item code in suggestion list in Moon Invoice by following the steps below.

1. Open the Moon Invoice application on your device or tap on this link.
2. Go to Settings ➜ App Settings. 
3. From the left panel, select the module where you want to update this setting. 
4. Click on Columns. 
5. Find Item Code in Suggestion List and toggle it On/Off as needed. 
6. Click Save to apply changes.