Hi After last update , black screen apear after starting any call what should I do?

Do you have a case on the iPhone? When making a call, there is a proximity sensor near the ear piece of your iPhone that will blank out the screen when you bring it up to your ear to prevent the accidental pushing of any buttons. If the phone goes dark when you make a phone call and it is not up to your ear, something could be blocking the sensor. A screen protector could also block the sensor if not the correct one for your iPhone. Try removing any and test your phone.