How to remove trusted device iCloud

See the following from Two-factor authentication for Apple ID - Apple Support

View and manage your trusted devices

You can view and manage a list of your trusted devices on iOS, macOS, and in the Devices section of your Apple ID account page.

On iOS:

1. Go to Settings > [your name].
2. Select a device from the list.

On macOS Catalina or later:

1. Choose Apple menu  > System Preferences.
2. Select Apple ID.
3. Select a device from the sidebar. 

On macOS Mojave or earlier:

1. Choose Apple menu  > System Preferences.
2. Select iCloud, then click Account Details.
3. Click the Devices tab.
4. Select a device from the list. 

On the web:

1. Go to your Apple ID account page.
2. Sign in with your Apple ID.
3. Go to the Devices section.

The device list shows the devices that you're currently signed in to with your Apple ID. Select a device to view device info like the model and serial number. Below that you can see other useful information, including whether or not the device is trusted and can be used to receive Apple ID verification codes.

You can also remove a trusted device by selecting Remove from Account from the device list. Removing a trusted device will ensure that it can no longer display verification codes and that access to iCloud, and other Apple services on the device, is blocked until you sign in again with two-factor authentication. If you need to find or erase your device before you remove it from your trusted device list, you can use Find My iPhone.