How to enable the bluetooth phone call function?

Start the Zepp app and go to "Profile > Amazfit GTS 2 > App settings". On the Phone page, turn on "Call on watch", then pair the watch and your phone through Bluetooth as instructed. Or you can try second mothed.
1. On your phone, go to Settings, then select "Bluetooth" to turn on the Bluetooth, and set the phone to be discoverable. On the watch, go to App list > Settings > Network and connections > Bluetooth. Ensure the Bluetooth is turned on.
2. Find the watch in the search results for available devices on your phone, and tap to pair them. Or, find your phone in the Bluetooth search results on the watch, and tap to pair the devices.