You can use the Find My app to remove a device from your Devices list or turn off Activation Lock on a device you already sold or gave away. When you remove Activation Lock, someone else can activate the device and connect it to their Apple Account.
If you still have the device, you can turn off Activation Lock and remove the device from your account by turning off the Find My [device] setting on the device.
Note: Finding devices isn’t available in all countries or regions.
If you’re not planning on using a device, you can remove it from your Devices list. The device may need to be offline in order for you to remove it.
The device appears in your Devices list the next time it comes online if it still has Activation Lock turned on (for an iPhone, iPad, iPod touch, Mac, or Apple Watch), or is paired with your iOS or iPadOS device (for AirPods or Beats headphones).
Do one of the following:
For an iPhone, iPad, iPod touch, Mac, or Apple Watch: Turn off the device.
For AirPods: Put AirPods in their case and close the lid or turn the AirPods off.
For Beats headphones: Turn off the headphones.
Open the Find My app What to do before you sell, give away, or trade in your iPhone or iPad and What to do before you sell, give away, or trade in your Apple Watch, or buy one from someone else and Remove a device from Find Devices on iCloud.com in the iCloud User Guide.