This article explains two ways you can transfer calls from your Apple Watch to your iPhone, as well as how to ping your phone if you can't find it.
How to Transfer a Call from Your Apple Watch to Your iPhone
The Apple Watch is great for taking and receiving calls hands-free, but sometimes it’s better to talk through a handset. There are two ways to switch a call from your Apple Watch to your iPhone, depending on whether you’ve already accepted the call or how you feel about putting your caller on hold.
You can transfer a phone call from your Apple Watch to your iPhone before you answer the call.
When a call comes in, select 'More' (three dots) on your Apple Watch.
