Unfurl keys your data to a random code, not your name — so deletion works by that code. You can find it in the app under Account → Your random code. Deleting removes your account and all server-side data tied to the code. Data on your own device is removed from the app's Account screen.
Lost your code? If you signed in with Apple, email privacy@unfurllife.com and we'll verify and delete it for you. Guest data never leaves your device — deleting the app removes it.