If you want to add Headers, Footers, and Footnotes to your Google Docs document, then this screenshot tutorial will help you.

The Explore feature includes the ability to add a properly formatted citation footnote in a Google Doc on the web. At least three major third-party citation services offer Google Docs Add-ons that ...

It will add the image to your page, plus a superscript number and a source link to the bottom of the page. To delete a footnote, simply delete the superscript number in your text.