You can use with notation to insert any element into a column:

>>> col1, col2, col3 = st.columns(3)
>>>
>>> with col1:
...    st.header("A cat")
...    st.image("https://static.streamlit.io/examples/cat.jpg")
...
>>> with col2:
...    st.header("A dog")
...    st.image("https://static.streamlit.io/examples/dog.jpg")
...
>>> with col3:
...    st.header("An owl")
...    st.image("https://static.streamlit.io/examples/owl.jpg")

^{(view standalone Streamlit app)}

Or you can just call methods directly in the returned objects:

>>> col1, col2 = st.columns([3, 1])
>>> data = np.random.randn(10, 1)
>>>
>>> col1.subheader("A wide column with a chart")
>>> col1.line_chart(data)
>>>
>>> col2.subheader("A narrow column with the data")
>>> col2.write(data)

^{(view standalone Streamlit app)}