Go to the Settings page on Koinly and click on Account. You should see a "Delete my account" button at the bottom. Press that and confirm that you want to delete your account.
Koinly will permanently erase all your data from our servers.
If you can't find the Delete account button, you can also submit an account deletion request by emailing [email protected] with the subject "Delete my account". Ensure you are sending the email from your registered email address.