To use Siri on your iPhone, you need first to turn on Siri, then activate it with the command “Hey Siri.” Here is how to enable Siri on your iPhone
How to Set Up Siri - iPhone and Mac Guides
How to use Siri on iOS, Mac, AirPods, and Apple Watch - Android Authority
Use Siri with AirPods (3rd generation) - Apple Support
How to Make Siri Kid Friendly - GadgetMates
How to change Siri volume and speaking rate – Apple Support (UK)
Understanding 'Hey Siri' — how to use it, commands, and more
Find out what Siri can do on iPad - Apple Support
Search with Spotlight on Mac - Apple Support
Use AssistiveTouch on iPhone - Apple Support
Set up Family Sharing on Mac - Apple Support
The complete list of Siri commands - CNET
How to turn off Siri on your iPhone or iPad