Copy the website URL of streamlit app (such as https://licenzart-startnewapp-app2-ceap85.streamlitapp.com/)
Go to google sites, insert <> (embed)
Insert by URL, paste the URL
Add ?embedded=true at the end of the URL (such as https://licenzart-startnewapp-app2-ceap85.streamlitapp.com/?embedded=true)
Click insert, Done!