To do that you need to do a few things. First off you would need to set a static IP address for your ESP32. You can either do that in the sketch itself or use your router configuration to assign a static address to a specific MAC address. Secondly you need to open your router just enough to allow users in. You could use port forwarding (Recommended) or setup a DMZ. Port forwarding basically means if your router receives a request on, say, port 80 (Normal HTTP request) then forward that request to a specific IP address (The static address of your ESP32). Thirdly to access with a proper domain name instead of an IP address (Which could change at any time by your ISP) you need to set up dynamic DNS (There are free ones out there). You run a script on a local computer that updates the DynDNS service daily to make sure it has the correct WAN address of your router. Finally you need to set username/password access for the ESP32 to stop unauthorized users accessing the ESP32.

Hi Steve.
Thanks for your detailed explanation.
Thuc Minh Bui, I see that you have bought the “Build Web Servers with ESP32 and ESP8266” course. There’s a section at the end of the eBook that shows how to access your web servers from anywhere.
Regards,
Sara

Forgot to add that you can also use Telegram.

Hi Steve,
How do you use Telegram?

The tutorial I linked to will show you how.

Hi.
Here’s all our tutorials about telegram: https://randomnerdtutorials.com/?s=telegram
Regards,
Sara