It depends on the specific style manual/guide that you are following. There are some common styles that lots of places use, such as Chicago, APA, MLA, and AP. Each field tends to have a specific style that is common or required in it. Check the manual for the specific style that you're using. Some styles use in-text citations and some use footnotes, and where the footnote is placed should also be marked in the guide.
Footnote marks at end of a sentence?
2 Answers By Expert Tutors

Alexandra E. answered 03/18/19
Bachelor's in Writing and Rhetoric with Writing Tutoring Experience
The APA, Chicago, and MLA style guides state that superscripts go after the punctuation. This includes when the citation follows a clause rather than the end of a sentence. However, if the punctuation is a dash, the superscript should come before it.
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