Use Siri dictation on Apple TV
You can use the Siri button 
on the Siri Remote to search within apps or enter text, user IDs, and passwords with your voice instead of typing.
Use dictation to search in supported apps
On the Home Screen and in supported apps such as Music and the Apple TV app, you can quickly dictate searches without having to navigate to the app’s search screen.
Press and release the Siri button
on the Siri Remote. When the search field appears, press and hold the Siri button, dictate a search term, then release the Siri button.
Speak text instead of typing it
With a text entry field highlighted onscreen press and hold the Siri button
on the Siri Remote, speak whatever you want to enter in the text field, then release the Siri button.
Speak user names and passwords
If a text field tells you to spell out characters instead of speaking words, press and hold the Siri button
on the Siri Remote, speak the letters, numbers, and symbols you want to enter, then release the Siri button.Say “uppercase” to enter an uppercase letter.
Siri recognizes many domain names such as icloud.com, so they don’t need to be spelled out.
You can use phonetic or military alphabet pronunciations, such as alpha, bravo, charlie, delta for A, B, C, D, and so on.
You can say “Clear” to delete the characters you just entered.
Clear applies only to characters spoken during the current dictation entry. For example, if you say “A, B, C,” then press the Siri button again and say “1, 2, 3, clear,” the numbers are deleted but the letters remain.
Note: Dictation sends information, such as voice input and location, to Apple to process requests. Voice input from spelling dictation of user names and passwords isn’t sent.
Turn dictation on or off
Open Settings
on Apple TV.Go to General > Dictation, then turn dictation on or off.