How to get Id using razor pages jquery in asp.net entity framework project?

I have a cshtml file with a form:

<div class="widget-content widget-content-area">
                            <form id="ticketdata" action="/Ticket/[email protected]" method="post">
                                <input type="hidden" asp-for="@Model.TicketId" />
...
...
...
<button id="btnticket" type="submit" class="btn btn-primary" onclick="CreateTicket(">Create Ticket</button>
                            </form>

In the first field I am selecting a Name from a drop down menu who has a unique userId. Based on the UserId I am fetching other details as well(and that’s working).
Here is the script for that:

$("#CustomerName").change(function () {
            var CustomerName = $("#CustomerName").val();
            $.ajax({
                    url: "../Ticket/FetchCustomerAddress",
                    data: { userId: CustomerName },
                    type: "Get",
                    success: function (data) {
                        $('#Address').val(data.address);
                        $('#City').val(data.city);
                        $('#ZipCode').val(data.zipCode);
                        $('#CustomerName').val(data.customerId)
                    }

After filling the form, at the time of submission. I want that userId for further operations. But I am not getting those details. I am only getting other details in the form and not the selected userId.

In the Ticket model, I have a parameter userId.

How to get that userId in the controller? using jquery or javascript?