Use case:
In a manufacturing scenario, the item is manufactured and the serial numbers are generated once the Stock entry is submitted.
But if there is a need for creating the list of serial numbers without auto creation (dynamically as per requirement). How can the serial numbers be generated?
Go to Item list --> Create new item --> Check Has Serial Number
Go to Serial number doctype --> Create serial numbers
While manufacturing, Work order --> Finish --> Stock entry --> Select serial numbers as per the manufacturing quantity.
This allows you to select Serial numbers dynamically at the time of manufacturing.