Yes, it is allowed to upload handwritten documents on Stuvia.
However, it is important to carefully check before uploading whether the document is clearly readable. Please make sure that:
your handwriting is easy to read
all pages are scanned neatly and completely
the scan quality is sharp and clear
the document is not crooked, blurry, or incomplete
In addition, the copyright rules also apply to handwritten documents. This means you may only upload content that you created yourself or that you have permission to share.