It's the second time I need to change the status bar color in a Xamarin.Forms (Android) and I didn't remember how to do it.
As I don't want to search it again, I decided to add the information here.
The status bar is the top part of the application where you can find the battery level, the network status,...
In your Android project, just add the following line in the styles.xml file and use the color you like:
<item name="android:statusBarColor">#3F4550</item>