You can add a header or footer in Google Docs from the 'Insert' menu. Google Docs automatically adds superscript numbers to your document when you insert a footnote in the document footer.

3] How to add a Footnote in Google Docs If you want to add citations, comments, or even references, you can use a footnote for these things in Google Docs.

You can add footnotes to a Google Doc on the web or in the Google Docs mobile app. It's easy to add footnotes in Google Docs on the web by using the toolbar to select "Insert," and then "Footnote ...

For math, science, or even a footnote, here’s how to superscript in Google Docs. Learn how to apply the superscript format on the web and in the mobile app.