You must use Google Docs built-in header styles for this to work. To add a heading in Google Docs, highlight the text you want to turn into a heading, select Format > Paragraph Styles, and select a ...

How to use AI to summarize a Google Doc with AI Google Step 1: Open a document on Google Docs and highlight to select the text you would like Gemini to help you summarize.

If you want to be diligent about proving your sources within Google Documents, Grammarly has a new feature you'll want to use.