Store Review Controller
You can ask users to rate and review your app at appropriate times throughout the user experience. Make the request when users are most likely to feel satisfaction with your app, such as when they’ve completed an action, level, or task. Make sure not to interrupt their activity.
To give users an easy way to provide feedback on the App Store without leaving your app, use the ISN_SKStoreReviewController. You can prompt for ratings up to three times in a 365-day period. Users will submit a rating through the standardized prompt, and can authenticate with Touch ID to write and submit a review.
Ensure that your support contact information is easy to find in your app and on your App Store product page. It gives users a direct way to reach you if they encounter difficulties, and gives you an opportunity to resolve negative experiences that may otherwise lead to poor reviews.
See the example below:
using SA.IOSNative.StoreKit; ... ISN_SKStoreReviewController.RequestReview();
The result will be a popup similar to the one on a picture below:
You can't get the result of the review request, or find out how many stars user has given your app. The reason is, Apple wants users to only do a fair review, and this is prohibited for app developers to give any kind of reward to users for a positive feedback.