Activate Siri, the Search app, or dictation on Apple TV
The Siri/Search button 
on the remote lets you control Apple TV with your voice, search using dictation in supported apps, and dictate text.
Activate Siri to control Apple TV, search, or make a query
Press and hold
on your remote, speak a command, search term, or query, then release the button.
Activate the Search app
In countries or regions where Siri isn’t supported, press and hold
on your remote to open the Search app 
.
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
on your remote.When the search field appears, press and hold
, dictate a search term, then release the button.
Use dictation to enter passwords and other text
With a text entry field highlighted onscreen, press and hold
on your remote, speak what you want to enter in the text field, then release the button.To spell out characters instead of words, speak the letters, numbers, and symbols you want to enter. Follow these guidelines for better dictation:
Say “uppercase” to enter an uppercase letter.
You don’t need to spell out common domain names such as icloud.com.
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.
To disable dictation, go to Settings 
on Apple TV, go to General, then select Dictation to turn it off.