Read the Understanding Android API Levels link below.
Visual Studio for Windows:
1.png
Visual Studio for Mac:
2.png
Target Framework – Specifies which framework to use in building your application. This API level is used at compile time by Xamarin.Android.
Minimum Android Version – Specifies the oldest Android version that you want your app to support. This API level is used at run time by Android.
Target Android Version – Specifies the version of Android that your app is intended to run on. This API level is used at run time by Android.
Manifest Entries:
Visual Studio for Windows:
![4.png](https://upload-images.jianshu.io/upload_images/4816610-1e12e512c4d00511.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)
Visual Studio for Mac:
4.png