There many ways to evaluate the goods ,but which the best in IFORS , GAAD 1. FIFO 2. LIFO 3.weighted average

Ok, I think you mean 'IFRS' and 'GAAP".Well, the thing is under IFRS or IAS2 to be precise, inventory should be valued at lower of cost or NRV(Selling Price - Costs to Sell).Under GAAP, it is required to state inventory at lower of cost or replacement value i.e. its market value.So ultimately, a company would want to use a method of valuation that is consistent with the accounting principles it applies.Method selection would also be affected by the method of movement of the inventory.Eg. Using IFRS to value Mobiles, it would be approriate to use LIFO, as it is likely that the latest models would be the most in demand. The ones that remained unsold in stock at the year end would then be carried at lower of Cost or NRV.For FIFO, think about products such as rice or coffee, the older they are the more their price increases.So, the older goods are likely to be sold first. It would be more approriate to use FIFO in this Case.For a product where there were a lot of closely priced products Weighted Average would be appropriate. For compliance with the accounting Regulations, it is more likely that the company at the year end carries out assessment of carrying value based on IAS or GAAP. Because it is unlikely that during the entire year using any of these methods would give an accurate value under either IFRS or GAAP.