If the Inventory Detail icon is not displayed on the transaction and there are no known issues in the system, it is possible that the form is customized and the field is hidden within the form. Follow the steps below:
1. Navigate to Setup > Customization > Transaction Form > Edit the custom transaction form.
2. Under the Screen Fields tab > Main subtab > Inventory Detail line,
- Mark the checkbox under Show column.
- Set field to Normal under the Display Type column.
3. Hit Save