I have an Iphone 8. On my old Samsung TV I can cast from Chrome to the TV so I can watch videos that aren't on Youtube. How do I do this with my new ROKU? It doesn't show up as an option.
You can't natively cast from Chrome to Roku.
If you have a Roku TV, you'll need to buy a chromecast dongle, plug it into one of your HTMI inputs, and select that input from your TV's home screen.
You can buy the basic chromecast which supports 1080p (HD) sells for about $35. If you want it to support 4KHD, you'll need the Chromecast Ultra, which costs $69.
Thanks for the inquiry.
Please be aware that screen mirroring with a Roku device or Roku TV is not supported with iOS® or Apple devices.
For more information about screen mirroring, visit our Support page here: How do I use screen mirroring with my Android™ or Windows® device?