1. In your .bashrc (or .bash_profile if you are on OSX) or .zshrc find the lines that source asdf.sh and the autocompletions. The lines should look something like this:

    . $HOME/.asdf/asdf.sh
    . $HOME/.asdf/completions/asdf.bash
   

   Remove these lines and save the file.

2. Run rm -rf ~/.asdf/ to completely remove all the asdf files from your system.

That's it!