How to POST file in a FormData Object from AngularJS to ASP.NET

Question

I'm trying to screenshot an invoice page in html as canvas with HTML2CANVAS, then create a pdf with pdfmake, I need to send the pdf file to the backend via http post, I have this function :

 $scope.createPdf = function () {
    html2canvas(document.getElementById('exportthis')).then(canvas => {
        var data = canvas.toDataURL();
        var docDefinition = {
            content: [{
                image: data,
                width: 500,
            }]
        };
        var file = pdfMake.createPdf(docDefinition)
        var Fileblob = file.getBlob((Blob) => {
            Blob.lastModifiedDate = new Date();
            Blob.name = "Invoice.pdf;"
            console.log(Blob);
            var fd = new FormData();
            fd.append('file', Blob, 'Invoice.pdf');
            $http.post("/Home/SendInvoice", {data: fd})
                 .then(function successCallback(data) { }, 
                       function errorCallback(response) {
                             console.log(response.statusText);
                       })
                 .finally(function () {
                 }
            );              
        });
    });
};

I tried FormData and sending the Blob alone but it shows null in the backend.

 public JsonResult SendInvoice(HttpPostedFileBase Attachement)
    {
        //Send Email with the file as an attachement
        *
        *
        return Json("Email Sent", JsonRequestBehavior.AllowGet); ;

    }