You can control the font and other properties of all your footnotes, by modifying the corresponding style. This is controlled by a Page Style (the fourth icon under Format / Styles and Formatting), named 'Footnote' (don't confuse this with the Paragraph style of the same name!). It might have a horizontal line or extra space above it, or other effects. The 'Footnote Area' is the space reserved at the bottom of a page to put footnotes in.This is controlled by a Paragraph Style (the first icon under Format / Styles and Formatting), named 'Footnote'. The 'Footnote' is the paragraph(s) of text that appears at the bottom of the page.This is controlled by a Character Style (the second icon under Format / Styles and Formatting), named 'Footnote Characters'. This is the same number or symbol as the 'Footnote Anchor', but can be formatted differently for example, it might or might not be superscripted. The 'Footnote Characters' is the number or symbol at the start of the 'Footnote'.The format of this character or number (font, size, superscripting, etc) is controlled by a Character Style (the second icon under Format / Styles and Formatting), named 'Footnote Anchor'. The 'Footnote Anchor' is the number or symbol that occurs in the main text, typically superscripted, and often an automatically-generated number.Taking footnotes first, the main parts are these:

Endnotes work the same as footnotes, with 'Footnote' changed to 'Endnote' everywhere.

Each part has a style that you can change, for example by using Format / Styles and Formatting. Formatting footnotes and endnotes is a bit complicated, because there are so many parts.

How to remove superscript in openoffice