If there is no option to create an account in the app, is there no need to provide the option to delete an account?
App Store Review Guideline 5.1.1(Account deletion within apps)
I have the same question on this. We have a LOB app and admins manage users, a user can't register and create an account themselves. It'd make sense that if a user can't create an account, they shouldn't be given the option to delete an account. We'd like to clarify though as it'd be a major shift in thinking and management of user accounts for our app.