It's in Settings > Project My Screen. It's baked into the OS.
Basically it shares to any screen on the same WiFi network. This is why I asked about what you want to share to. If your TV (for example) lacks a Smart Connection of soem sort then you can't do it without a dongle. My TV has a Sony Smart Blu-Ray player attached so I can just use Project My Screen to mirror my 1520 on my TV screen.
I'm using win 10 but I guess you talk about feature that's baked into action center settings. And that says my device doesn't support it when I open it.