Please follow the below steps:-

1. Open Inventory Management module from Dashboard.
2. Enter your quick access password.
3. At the top left, click on the three lines (Hamburger) button
4. Select the Department option from the Item Master menu.
   
   
5. Select and click on the Department.
6. Turn on the toggle button of the Age restriction option and select age criteria from the dropdown list.
   
   
7. Click Save.