Setup

Webmin is a web-based system administration tool for Unix-like servers, and services.
Using it, it is possible to configure operating system internals, such as users, disk quotas, services or configuration files, as well as modify, and control open-source apps.

Run the following commands to install it on your raspberry pi:

        echo "deb https://download.webmin.com/download/repository sarge contrib" | sudo tee /etc/apt/sources.list.d/webmin.list
        wget -qO - https://download.webmin.com/jcameron-key.asc | sudo apt-key add -   
        sudo apt update
        sudo apt install webmin --install-recommends
        

You can unblock port 10000 which is used by webadmin from ufw sudo ufw allow 10000
The login credentials are the same as your pi's credentials.