Garmin compatible with iphones

Do you have Venu 3? It should already be compatible with iPhone to a certain extent. You can pair the watch with your iPhone to receive notifications, make and receive calls, and use voice assistants like Siri. However, replying to text messages directly from the watch is currently limited to Android devices.

Setting Up Voice Assistant on Your Garmin Watch | Venu® 3 | Garmin Customer Support

This isn't a Garmin issue. It's Apple's decision to lock down iOS for security reasons which means no 3rd party wearables can take calls, send messages. If that's important to you, you will either have to switch to Android or switch to an Apple Watch.

The community from apple said that it is garmin issue to make  garmin hardware compatible with iphone. I don’t have garmin watch yet, because I want to make sure that I will be able to use all functionalities which I paid money for and which are listed in the watch specification as available for users. For now, as I know, you cannot answer text messages and talk when you pick up call, but this watch has microfone. And I was informed by Garmin sellers it is not available now(after some of the iphone updates) and they cannot make sure that it will be in the future available again. 

4881539 said:

And I was informed by Garmin sellers it is not available now(after some of the iphone updates) and they cannot make sure that it will be in the future available again. 

Because its Apples limitation.