Hi @paul_hong,
First, Welcome to the Streamlit community!

Are you trying to create a global config.toml file to make a theme that all of your apps will have? If you have Streamlit 0.79 and above then you can do this.
So Streamlit doesn’t have a config file in that folder, it uses the configuration options as flags when you streamlit run my_app.py. All you have to do is actually make a file called config.toml and then put in the config options you want to have.
This can be done globally in your ~/.streamlit/ folder or for each local directory so different projects can have different configurations/themes path/to/app/.streamlit/config.toml
Happy Streamlit-ing!
Marisa