To edit the next app on Android, you can download Termux from the Play Store. Now you can use the inbuilt nano editor to edit your next app and another method is to push code into GitHub and then edit.
Let me walk you through how you can edit your next app on Android while using Termux.
 Editing the next app While Using Nano Editor
There are no code editors that support the latest ES6 module on Android, so you can also use the built-in nano editor on Termux to edit the next app. Now, let's first dive into the step.
First, go to the Play Store, type Termux in the search bar and download it. After downloading open the app and write this command for Termux storage permission,
termux-setup-strorage
Allow the storage permission and now you need to run this command to update the package.
pkg update && upgrade
After updating the package, you need to install Nodejs while running commands.
pkg install nodejs
  Creating NextJS APP with Termux Terminal
To create the next js app on Android you can run this command,
npx create-next-app@latest
It will give you options to choose from. You must reject the Turbo Pack since Termux doesn't support the latest future. If you have selected the turbo pack, you can disable it by modifying the package.json file.
What is your project named? my-app
Would you like to use TypeScript? No / Yes
Would you like to use ESLint? No / Yes
Would you like to use Tailwind CSS? No / Yes
Would you like your code inside a `src/` directory? No / Yes
Would you like to use App Router? (recommended) No / Yes
Would you like to use Turbopack for `next dev`? No / Yes
Would you like to customize the import alias (`@/*` by default)? No / Yes
After creating the next js app while using the Termux terminal. Now get access to the project while running this command,
cd my-app
Now you can edit any of the individual files while running this command.
nano package.json
That's how you can edit your next app on Android while using the inbuilt Nano Editor on Termux but it's a very slow process, especially on a small screen.
 Editing the next app on Android while using Github
Now, let's install the git while issuing this command,
pkg install git
Now check the present working directory while running these commands.
pwd
and,
cd folder name
We can't log in with a username and password because GitHub removed the password authentication on August 13 2021; we need to set the SSH key to access the GitHub repository. Open Termux and run this command to generate an SSH key. Also, add your email address.
ssh-keygen -t ed25519 -C "your_email@gmail.com"
Now, you can run this command to access the public SSH key.
cd .ssh
and cat ed25519.pub
Copy this public SSH key, Go to your GitHub account and click on the repository setting icon and you will see the option of deploy keys add your deploy key here and do not forget to checkmark the write access feature so that you can push your code,
Now let's run this command,
git init
After that, add the README.md file while using this command,
git add README.md
You can add your first commit while running this command,
git commit -m "first commit"
Then run this command to set your main origin,
git branch -M main
Now, run this command to check the connection between the GitHub repository and your local Termux terminal.
ssh -T git@guthub.com
Now you need to set the git remote origin,
git remote set-url origin git@github.com:your_git_user_name/repository_name.git
and
git add .
Now you can run this command to push your code to GitHub.
git push -u origin main
Now, you can edit your next app on GitHub in Android. You can also use codespace for the terminal. And vs code server for editing the next app on GitHub.