doc: update the Overview page

README_API_DOC.md

@@ -1,5 +1,9 @@
-# Prebid Mobile iOS SDK
+# Prebid Mobile SDK - iOS API Reference
 
-To work with Prebid Mobile, you will need accesss to a Prebid Server. See [this page](https://docs.prebid.org/prebid-server/overview/prebid-server-overview.html) for options.
+Prebid iOS SDK is an open-source monetization library that allows you to integrate header bidding demand partners into the mobile app in various ways. The integration documentation can be found [here](https://docs.prebid.org/prebid-mobile/prebid-mobile.html). 
 
+This section is autogenerated documentation describing the SDK's public classes, methods, and other code structures. It doesn't provide any integration guides but always provides updated API references. 
 
+The documentation is generated for each SDK release.  
+
+If you see any inconsistency or want to improve the process, you are always welcome to contribute to [Prebid Mobile iOS SDK](https://github.com/prebid/prebid-mobile-ios) on GitHub.