I was under the impression the source authors publish to arxiv was a latex file
I looked up the submission formats, and it looks like if you authored the paper in TeX/LaTeX, they do not accept pre-rendered versions of the document.
https://info.arxiv.org/help/submit/index.html#formats-for-te...
But if you did not author it in TeX/LaTeX (e.g., Word, Google Docs, etc.) it appears you can upload a PDF or HTML yourself.