The command line, terminal, prompt, dos, bash, or whatever you want to call it, kind of boils down to the same thing. You have a "terminal session" via some kind of window or prompt, to type commands. This is computing at its simplest in many ways. The "terminal" is where you type your input, whether that is "Terminal" on macOS, or "Windows Terminal" on Windows, or something else like Warp. The commands you use might be DOS, Bash, Zsh, PowerShell or something else. You might also be connected to a different computer via SSH or Telnet.
A good place for beginners is Command line crash course - Learn web development | MDN because Mozilla do a good job with their documentation. I have also documented a number of these things here, so check out the following: