I forgot my MacBook firmware password, how can I reset it?

Ahmadgarba. Unfortunately you can't reset your MacBook Air Firmware password because that's the motherboard password, and you'll not find any option to reset it. But you can schedule a date on an Apple Store, or an authorized store by Apple to turn it off. Obviously you will need to bring your receipt or something that proofs your purchase.

Contact Apple Support, using the Get Support link in the upper right.

Apple has (had?) a tool to reset the firmware password in that era.

They may or will expect a purchase receipt.