Read for information on the kinds of files that can be uploaded as drawings. For information on what the quality of the drawing needs to be read this article.
PDF's - The preferred file format
You can upload a PDF document containing the pages of drawings. This can be done by either scanning the printed pages or, if you are using a different CAD software package then you can use the Microsoft Print to PDF print function. (Available in Windows 10.)
Other image files
Image files such as jpeg (or jpg), png or bitmap (bmp) are accepted, but not preferred. They do not allow you to collate multiple pages into 1 file as a PDF does.