You can earn Fortnite Drops in the
official broadcast or by watching any
Drop-supported Twitch channel.
Note: You'll need to make sure your Twitch account is connected to your Epic Games Account prior to the event. You can do this in your Connections settings on your Epic Games Account.
Once an approved channel is viewed for the required time for the current Twitch Drop event, a notification will appear on your Twitch account confirming you have met the eligibility requirements. You can then navigate to the Twitch inventory section to claim the content.
Be sure to claim it in the time frame stated in the notification.