how do i found out if a company is certified manufactury (made for iphone) chargers and not fake.

It is not possible to confirm that an adapter is genuine by inspecting its exterior, and inspecting the interior to identify engineering shortcomings that differ from Apple's design destroys the power adapter.

Many counterfeit adapters can be identified through obvious misspellings on their case, but the only way to be absolutely certain you are using a genuine Apple power adapter is to purchase it from Apple or an authorised Apple reseller. Counterfeit and potentially dangerous power adapters bearing fraudulent consumer product safety agency approval markings are very common.

All genuine Apple products, and power adapters, have unique serial numbers. Counterfeit power adpaters, do not have unique serial numbers. Look at two power adapters of the same model number and, if they share a serial number, the products are obvious counterfeits.