Scrive don't delete user accounts as a safety-rule since it contains agreements, but by following these instructions you will be able to delete your account.
What is good to know before you delete your account is that if you delete a user-account, the documents that the user has don't get removed since they belong to the user group. If the user group were to be deleted, then the documents disappear.
If you have created a free account via https://www.scrive.com/get-started/ you can remove it by navigating to "Account" and then clicking on the "Delete" button at the bottom of the page.
If you're using Scrive Classic and want to delete your account you can do this by navigating to "Account" -> "My info", scroll down and you'll see a big red button named "Delete". Here you can delete your account.