Do I need to update my address on my iphoneX if it connects to the internet or is it automatic?

The article you linked from explains that your location is based on your actual location, not your home or billing address.

In the current technology, only your Emergency Contacts are sent your location directly. With the new iOS Apple announced that 911 calls in the US would also start sending location information to 911 emergency services. Currently, the iOS uses cell towers and Wifi access points to determine your location.

See these articles for more info:

Use Emergency SOS on your iPhone - Apple Support

https://www.cnbc.com/2018/06/18/apple-will-automatically-share-emergency-locatio n-with-911-in-ios-12.html

Best,

GB