Control Siri another way
1 Type to Siri
Until now, speaking was your main way to ask something of Siri. Typing on a keyboard only figured if you wanted to correct something Siri misheard. iOS 11 has a new Type to Siri option In Settings > General > Accessibility > Siri. If enabled, typing is used to interact with Siri when you hold the Home button.
2 Combine with Dictation
You can still use your voice with Siri if iOS’s Dictation feature is enabled in Settings > General > Keyboards. Open Siri, tap the microphone key, speak, then tap the keyboard icon followed by Done.
3 Hey Siri
Even with Type to Siri enabled, the assistant will switch to voice control if you call for its help by saying “Hey Siri.”
On devices that respond to that phrase while running on battery power, this gives you the best of both worlds: voice control initiated with your voice, and a press of the Home button followed by typing when speaking isn’t a good option.
Devices that respond to “Hey Siri” while running on battery power are the iPhone 6s, iPhone 6s Plus, iPhone 7, iPhone 7 Plus, 12.9-inch and 10.5-inch second-generation models of iPad Pro, and the 9.7-inch first-generation iPad Pro.