The instructions in this blog post are outdated. Please have a look at the new instructions.
Exposing your Home Assistant instance outside of your network always has been tricky. You have to set up port forwarding on your router and most likely add a dynamic DNS service to work around your ISP changing your IP. After this you would be able to use Home Assistant from anywhere but there is one big red flag: no encryption.
This tutorial will take you through the steps to setup a dynamic DNS for your IP and allow trusted encrypted connection to it - for free using DuckDNS and Let’s Encrypt.