Duplicating a command as output. Whats wrong?

Bash is a Unix shell and command language written by Brian Fox for the GNU Project as a free software replacement for the Bourne shell.
It has been distributed widely as the default login shell for most Linux distributions and Apple’s macOS.
I am totally new and trying to understand Linux; however, I am unable to do anything in Bash, in that every command input results in duplicate output, and nothing else. Whats wrong?
Thank You

sorry, I don’t understand ‘duplicate output’ . Can you share a screenshot or error message?