Apple is playing games with screen Mirroring

I have tried multiple times to get screen mirroring to work with both my computer, iPad, and iPhone. But to no avail, however if you go to Apples App store you find lots of Airplay and Screen Mirroring apps that like to charge you a subscription fee. Mirroring and Airplay used to be as simple a click away now many claim you just adjust networks settings, passwords. I have too smart TV only on one does the code to get Airplay to pop up but once entered it fails to send the video stream.