How do you use telnet app on android smart phone?

To use a Telnet app on an Android smartphone, first, download a Telnet client from the google Play Store, such as "Termux" or "JuiceSSH." Open the app and enter the Telnet command along with the desired hostname or IP address and port number (e.g., telnet example.com 23). Once connected, you can interact with the remote server using the command line interface. Make sure your phone is connected to the internet for the connection to work.