Pdf uploading without using input box in php

I am using a javascript code to annotate the pdf within the browser and after annnotating i am saving it to mydevice and then uploading it using another form.

but i want it be uploaded into the local storage of web page and then upload automatically to my upload.php

function printPDF() {
    const printWindow = window.open('', '_blank');
    const printDoc = printWindow.document;

    for (let i = 0; i <= pdfDoc.numPages; i++) {
        pdfDoc.getPage(i).then(page => {
            const viewport = page.getViewport({ scale: 1.5 });
            const canvas = document.createElement('canvas');
            const context = canvas.getContext('2d');
            canvas.width = viewport.width;
            canvas.height = viewport.height;

            const renderContext = {
                canvasContext: context,
                viewport: viewport
            };

            page.render(renderContext).promise.then(() => {
                renderAnnotationsOnCanvas(context, i); // Render annotations on the canvas
                const imageData = canvas.toDataURL();
                printDoc.write('<img src="' + imageData + '" style="max-width: 100%;">');
                if (i === pdfDoc.numPages) {
                    printDoc.close();
                    printWindow.onload = function () {
                        printWindow.print();
                        printWindow.close();
                    };
                }
            });
        });
    }
}

this is output window we get after the print pdf get trigger this just an example:

This is my java script code to save the the annotated pdf