Step (1)
What is ngrok?
ngrok is a cross-platform application that enables developers to expose a local development server to the Internet with minimal effort. The software makes your locally-hosted web server appear to be hosted on a subdomain of ngrok.com, meaning that no public IP or domain name on the local machine is needed
ngrok is able to bypass NAT Mapping and firewall restrictions by creating a long-lived TCP tunnel from a randomly generated subdomain on ngrok.com (e.g. 3gf892ks.ngrok.com) to the local machine. After specifying the port that your web server listens on, the ngrok client program initiates a secure connection to the ngrok server and then anyone can make requests to your local server with the unique ngrok tunnel address.
Step (2)
Install ngrok in your Termux
Install ngrok in termux
($) apt update
($) apt install unzip wget
($) wget https://bin.equinox.io/c/4VmDzA7iaHb/ngrok-stable-linux-arm64.zip
unzip ngrok-stable-linux-arm64.zip
chmod +x ngrok
./ngrok authtoken <YOUR AUTH TOKEN>
./ngrok -help
./ngrok http 8080