Device Whitelists can be used to provide additional security when Zero Touch Provisioning (ZTP) is required. You'll find the whitelist management under Settings \ Device Whitelist.
When you create a whitelist you have the option to add or remove individual devices or upload a CSV file. The upload wizard will give you a link to download a csv template for your whitelist.
You can also export the whitelist as a CSV file to edit it locally and then upload again.