Just press and hold the power button on your Mac until it turns off.It’s a good idea to physically clean your MacBook Air, which makes it more attractive to buyers but more importantly, you need to protect your private data, credit cards, personal photos, and account information by erasing your MacBook Air data before you sell. If you're selling, giving away or trading in your Mac and want to leave it in an out-of-box state, don't use the setup assistant or your previously connected Bluetooth devices, if any.

After restart, a setup assistant guides you through the setup process, as if you're setting up your Mac for the first time.

After joining a network, your Mac activates.

To select a Wi-Fi network, use the Wi-Fi menu in the top right-hand corner of the screen.

You may be asked to select a Wi-Fi network or attach a network cable.

When reconnecting to a Bluetooth keyboard, you're asked to choose a language. If the accessory doesn't connect within 30 seconds, turn the accessory off and back on. If it needs to reconnect to a Bluetooth accessory, such as a keyboard or mouse, you may be asked to turn on the accessory.

Your Mac restarts and shows a black screen or progress bar.

Click Erase All Content & Settings to confirm that you want to proceed.

If you're asked to sign out of Apple ID, enter your Apple ID password and click Continue.

Click Continue to allow your settings, media, data and the other listed items to be removed.

Or click Continue to proceed without making a new backup.

If you're asked to back up your Mac before resetting it, you can open Time Machine and back up to an external storage device.

Enter the password that you use to log in to your Mac, then click OK.

An erase assistant will ask you to sign in with your administrator credentials.

After choosing Erase All Content and Settings, follow these steps to continue:

Macbook air wipe clean