There are some things your Apple Watch just cannot (or should not) do, like sending emails or searching the web.
You can still ask Siri to do these things, but she’ll ask you to take your request elsewhere — namely, to your iPhone. Here’s how Handoff works with Apple Watch.
When you ask Siri on your Apple Watch to do something she can’t quite handle, she’ll let you know that you can pick up the task on your iPhone. When you wake your iPhone, you’ll see a little microphone icon in the lower left corner of the screen.
All you need to do is swipe up on that icon. After you unlock your iPhone, you will be able to pick up the task from there.
Now you can use Siri to start tasks on your wrist and, when Apple Watch can’t handle them, you can pick them up on your iPhone without missing a beat. Hoorah!