You can use Chromecast, which costs about 35 euros. We devoted an entire folder , which I invite you to read. Know that other certified devices "Chromecast" you can now be marketed.
Google Cast devices allow you to easily cast all your entertainment on your TV or on your ..
You then download the latest version of the Chromecast app on your Android device. If your Android and Chromecast are paired, you just have to select it in the list. The option is also available in Settings> Display> Screen Broadcast (Android Settings> Display> Screen Cast).
There are also more traditional methods, but with a cable: MHL, HDMI ...