How to have a number formatted line item starting with zeros?
Eg. it should have a value like 0124 or 0001324?
You need to have text formatted line item instead to achieve this
@PulkitChawla21 as per @Himanshu1998's comments it will need to be text and you can apply the formula against the original numeric line item such as
RIGHT("00000000" & TEXT(numeric value), 8)