Is there any way that i can access health data from Microsoft Health Cloud in my iOS App.Are there any restrictions?
Yes, the Microsoft Health Cloud API is a web service, so it can be used by any client capable of HTTP requests. You'll need to manage the OAuth-based authentication within your iOS application (e.g. by hosting a web view that allows the user to sign-in with their Microsoft Account) but, after that point, it's just plain REST.
See the Getting Started documentation for more details about authentication and API.