Erase a device in Find My on Mac
If your Mac, iPhone, iPad, iPod touch or Apple Watch is lost or stolen or you’re planning to sell it or give it away, you should erase the device. To remotely erase a device, you must add it to Find My before it’s lost or stolen.
Note: See the Apple Support articles for full details about preparing to sell, give away or trade in your Mac, iPhone, iPad, iPod touch or Apple Watch.
If you’re part of a Family Sharing group and you set up location sharing with a family member before you want to erase a device, that person can help you erase your device using Find My. See Change Location Sharing preferences in Family Sharing.
What happens when you erase a device in Find My?
Activation Lock remains on to protect your device. Your Apple ID and password are required to reactivate it.
Apple Pay is disabled for your device. Any credit or debit cards set up for Apple Pay, student ID cards and Express Travel cards are removed from your device. Credit, debit and student ID cards are removed even if your device is offline. Express Travel cards are removed the next time your device goes online. See Use Wallet & Apple Pay.
Remotely erase a device
In the Find My app
on your Mac, click Devices.In the Devices list, select the device you want to erase, then click the Info button
on the map.Click Erase This Device.
Note: You can also Control-click the device in the Devices list, then choose Erase this Device.
Click Continue, then do one of the following:
For a Mac: For a Mac, you must create a numeric passcode even if you already have a password set up on your Mac. This passcode is distinct from your password and is only used when you mark your device as lost or want to erase it.
For iPhone, iPad, iPod touch or Apple Watch: If you’re not using one of your trusted devices, enter the passcode of the device you’re erasing.
Enter a phone number or message if you want to indicate that the device is going to be erased and how to contact you. The number and message appear on the device’s Lock screen.
Click Erase. Enter your Apple ID password or your family member’s Apple ID password, then click Erase again.
If your device is offline, the remote erase begins the next time it connects to a Wi-Fi or mobile network.
Instead of remotely erasing your Mac, you can erase it using Disk Utility 
(which removes Activation Lock) before you sell it or give it away. To remove Activation Lock, you can also just remove it from Find My. The next owner can then activate and use the device normally. See Activation Lock and Find My.
Cancel an erase
If you erase a device that’s offline and find it before it comes online again, you can cancel the erase request.
In the Find My app
on your Mac, click Devices.In the Devices list, select the device whose erase you want to cancel, then click the Info button
on the map.Click Cancel Erase, enter your Apple ID password or your family member’s Apple ID password, then press Return.
If you lose your Mac and don’t own an iPhone, iPad, iPod touch or another Mac, you can erase it using Find My iPhone on iCloud.com.
For information about using Find My with other devices, see the user guide for iPhone, iPad, iPod touch or Apple Watch, or the AirPods Support website.