I am developing one application for iOS. In that user can purchase doctor services. I dont have any idea about payment gateways. So, please suggest me which is the best payment gateway method and how to implement that in my iOS app. ( I am from India), i heard payment gateway methods depends upon the country.
Generally speaking, yes, your app will be rejected. According to section 11.2 of the App Store Review Guidelines for iOS (Login Required) any app that doesn't use In-App purchase will be rejected.
11.2 Apps utilizing a system other than the In App Purchase API (IAP) to purchase content, functionality, or services in an app will be rejected
Additionally, note that any purchase of real world goods or services is not allowed as per section 11.3. I suggest reading the whole document, or at least section 11 (and 20 if it's a charity app). That should give you a pretty good idea of what's allowed and what's not.
If you are purchasing digital content for use within the app you must use in-app purchase ,for real goods like book ,pencil,Cd you can use PayPal.
There are quite a few - also depends on your country as not all providers cover all countries. Take a look at:
https://www.braintreepayments.com/
and probably http://www.paypal.com
What you want is something that's easy to code for (securely) in iOS. All the above (as well as many others) have APIs and sample code that make connecting to process payments easy and secure.
EDIT
Just seen you've added that you're in India. Assuming that means that you want to process payments in India, then I think your options (as at July 2014) are more limited. Certainly stripe and braintree don't cover India. I believe PayPal do (although maybe not with their latest APIs), so that might be your best bet.
来源：https://stackoverflow.com/questions/24930200/which-is-the-best-payment-gateway-for-service-purchasing-in-ios-app