Inventory items need to be considered in financial vouchers where you use ledger heads that have the option Are Inventory Values affected? set to Yes. Similarly you will have the accounts of the type Sales and Purchases affecting inventory. When you enter a voucher (usually a Sales or a Purchase Voucher) a sub-screen pops up after the concerned ledger head and amount asking you to enter inventory item details.
The inventory details that you give in an accounting voucher (like Sales and Purchase Voucher) affects stocks by immediately updating them only if Tracking Numbers are not activated in F11: Features. Otherwise, the inventory allocation tracks against Goods In or Goods Out notes through tracking numbers.
The information that you need to give in the inventory allocation sub-screen depends upon the features enabled for the company.
A typical inventory allocation sub-screen appears as shown below.
Name of Item
Select the item from the list of items or press ALT+C to create a new item.