Downloading a file from a Streamlit App

I am trying to create an app that will accept a pdf file from the user, edit the in the browser, and then save it in the user’s system. I am editing the file after accepted it through the st.file_uploader() method. My question is:
How can I give the user an option to download in their system?

you can try this to provide a link to download a file:

st.markdown("<a href='' download=''>download the pdf file</a>", unsafe_allow_html=True)