protected void convertToPdfButton_Click(object sender, EventArgs e)
{
    // Create a PDF document
    Document pdfDocument = new Document();

    // Set license key received after purchase to use the converter in licensed mode
    // Leave it not set to use the converter in demo mode
    pdfDocument.LicenseKey = "fvDh8eDx4fHg4P/h8eLg/+Dj/+jo6Og=";

    // Add a page to PDF document
    PdfPage pdfPage = pdfDocument.AddPage();

    // Set user and owner passwords
    if (userPasswordTextBox.Text.Length > 0)
        pdfDocument.Security.UserPassword = userPasswordTextBox.Text;

    if (ownerPasswordTextBox.Text.Length > 0)
        pdfDocument.Security.OwnerPassword = ownerPasswordTextBox.Text;

    if (pdfDocument.Security.UserPassword != null && pdfDocument.Security.UserPassword.Length > 0 &&
        (pdfDocument.Security.OwnerPassword == null || pdfDocument.Security.OwnerPassword.Length == 0 ||
        pdfDocument.Security.UserPassword == pdfDocument.Security.OwnerPassword))
    {
        // A user password is set but the owner password is not set or is identical to user password
        // Set a different owner password
        pdfDocument.Security.OwnerPassword = pdfDocument.Security.UserPassword + "_owner";
    }

    // Set PDF document permissions
    pdfDocument.Security.CanPrint = printEnabledCheckBox.Checked;
    pdfDocument.Security.CanCopyContent = copyContentEnabledCheckBox.Checked;
    pdfDocument.Security.CanEditContent = editContentEnabledCheckBox.Checked;
    pdfDocument.Security.CanEditAnnotations = editAnnotationsEnabledCheckBox.Checked;
    pdfDocument.Security.CanFillFormFields = fillFormFieldsEnabledCheckBox.Checked;

    try
    {
        // Create a HTML to PDF element to add to document
        HtmlToPdfElement htmlToPdfElement = new HtmlToPdfElement(urlTextBox.Text);

        // Optionally set a delay before conversion to allow asynchonous scripts to finish
        htmlToPdfElement.ConversionDelay = 2;

        // Add the HTML to PDF element to document
        pdfPage.AddElement(htmlToPdfElement);

        // Save the PDF document in a memory buffer
        byte[] outPdfBuffer = pdfDocument.Save();

        // Send the PDF as response to browser

        // Set response content type
        Response.AddHeader("Content-Type", "application/pdf");

        // Instruct the browser to open the PDF file as an attachment or inline
        Response.AddHeader("Content-Disposition", String.Format("attachment; filename=Set_Permissions_Password.pdf; size={0}", outPdfBuffer.Length.ToString()));

        // Write the PDF document buffer to HTTP response
        Response.BinaryWrite(outPdfBuffer);

        // End the HTTP response and stop the current page processing
        Response.End();
    }
    finally
    {
        // Close the PDF document
        pdfDocument.Close();
    }
}