Admob.txt

//1- add google play service-ads 

//2- update the manifest.xml
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
	<uses-permission android:name="android.permission.INTERNET" />
	
//3- in manifest.xml application tage add these lines
	<activity android:name="com.google.android.gms.ads.AdActivity" android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize" android:theme="@android:style/Theme.Translucent" />
	
//4- layout 
xmlns:ads="http://schemas.android.com/apk/res-auto"
	 <com.google.android.gms.ads.AdView
            android:id="@+id/adView1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            ads:adUnitId="@string/Banner_Ads"
            ads:adSize="BANNER"
           />
       
 
    
 //Banner Ads 
          AdView  mAdView = FindViewById<AdView>(Resource.Id.adView1);
            var adRequest = new AdRequest.Builder().Build();
            // Start loading the ad.
            mAdView.LoadAd(adRequest);
//5- update string.xml file
<string name="Banner_Ads">ADD_ID</string>