The File Upload option type supports only one file per option. At the moment, multiple file uploads within a single upload field are not supported.
Workaround:
If you need customers to upload multiple files, you can:
Add multiple File Upload option fields (e.g., “Upload File 1”, “Upload File 2”, etc.)
Assign each options to the same product or option set.
This way, customers can upload more than one file using separate upload fields.