A:AnswerThis is a 4K TV, just play 4K enabled content.
While watching a video long press the Home button and select Info, this will display the resolution of the video that's playing.
A:Answerthis is a Amazon fire tv. it does not have Chromecast built in, a Google/Android TV will do that though. It does have a mirroring option but can be a bit finicky to set up. If you connect via HDMI, will work fine though.