Pandoc supports only a small subset of LaTeX commands and \scriptsize is not one of them. Why does it work anyway? Because unrecognized LaTeX (or ConTeXt or HTML) commands are passed unchanged to the LaTeX (or ConTeXt or HTML) writer. If you want to use pandoc to convert LaTeX to .docx, then you should stick to those commands that can be represented in pandoc's own markdown format.
Nevertheless: If you want to modify the produced .docx you can save the reference file using: pandoc --print-default-data-file reference.docx > custom-reference.docx
Update: The recent manual suggests using pandoc -o custom-reference.docx --print-default-data-file reference.docxto create custom-reference.docx
In custom-reference.docx you can change the following styles (be sure to actually change the style defined in the document, not just the sample text!):
paragraph
- Normal
- Body Text
- First Paragraph
- Compact
- Title
- Subtitle
- Author
- Date
- Abstract
- Bibliography
- Heading 1
- Heading 2
- Heading 3
- Heading 4
- Heading 5
- Heading 6
- Block Text
- Footnote Text
- Definition Term
- Definition
- Caption
- Table Caption
- Image Caption
- Figure
- Figure With Caption
- TOC Heading
character
- Default Paragraph Font
- Body Text Char
- Verbatim Char
- Footnote Reference
- Hyperlink
table
You can use the changed reference file by adding the option --reference-doc=custom-reference.docx.
reference.docx, I would not have thought to look for that option in the help/manpage. – Damian Vogel Dec 17 '18 at 12:49--reference-docdirective? It is not working on thepandoccommand line: the fontsize remains the same – WestCoastProjects Apr 25 '23 at 16:00custom-reference.docx, which I updated in the answer. So if anything does not work, please be more specific. Maybe you want to ask a new question, providing a minimal working example (MWE) – DG' Apr 25 '23 at 20:32