How do I turn off the "Add Links / Cite Sources" area when creating new Posts?

I cannot find where to turn this off. I want the simplest setup for users. If they want to share a link, they can put it in the body itself IMO.

This section is below to Post body and labeled:

Cite your Sources with a URL link to help readers verify facts or find more details.

I have looked through all settings several times and cannot find where to turn this off.

Thanks!