In MS word, how to reduce the gaps before and after footnotes

I would like to remove the space between the main text and the footnote separator, I have checked the draft view - footnote separator, there are no extra lines before or after the footnote separator. All my paragraphs and footnotes are using single spacing without adding space before or after. Not sure why this one-line space still exists.

Besides, how to remove the space between the footnote and the footer. The gap is even larger.

First I suggest you click Expansion arrow of Footnotes group > choose "Below text" for Footnotes > Apply.

Then chose the last line of main text > Right click, select Paragraph > In the Paragraph dialog box, click the Indents and Spacing tab, and make sure that Spacing After is set to zero. Change the Line Spacing to "Single".