please tell me, how to i creat to unit name of one item,
That depends on what you are creating:
If you are combining two input (raw) materials into one finished good then you use “Production Orders” - flour + yeast to make bread.
If you are combining two or more finished goods into a packaged item the you use “Inventory Kits” - bat + ball + wickets to make cricket set.
@Brucanna may have answered your question. But if you were asking about how to sell the same item in different units, such as each and box, you need two separate inventory items with different units of measure.