A family of Microsoft word processing software products for creating web, email, and print documents.
You will have to add one or more section breaks and then you can change the format of footnotes in the new section(s). For example, you can add a section break at the end of each chapter and then have the footnotes restart on each section.
Note that section breaks are not supported in Word on the web (in your web browser). You will need the full version of Word running under Windows or macOS.