Creating an Upload Button in HTML Element

Hi, I am trying to create an upload button that will allow for the upload of .html files, which unfortunately the Wix upload button does not support at all.

The only solution I can think of at the moment would be to create an HTML element with an upload button and use this to upload the files. Does anyone have any guides or tips on how to do this as I can’t figure out how to create an HTML button that actually uploads and sends the data to Wix.