How to include anti-forgery token in ajax request in ASP.NET MVC?

First Create a C# Helper function in a Class, so you can use it for other AJAX request also

public static MvcHtmlString AntiForgeryTokenForAjaxPost(this HtmlHelper helper)
{
    var antiForgeryInputTag = helper.AntiForgeryToken().ToString();
    // Above gets the following: <input name="__RequestVerificationToken" type="hidden" value="PnQE7R0MIBBAzC7SqtVvwrJpGbRvPgzWHo5dSyoSaZoabRjf9pCyzjujYBU_qKDJmwIOiPRDwBV1TNVdXFVgzAvN9_l2yt9-nf4Owif0qIDz7WRAmydVPIm6_pmJAI--wvvFQO7g0VvoFArFtAR2v6Ch1wmXCZ89v0-lNOGZLZc1" />
    var removedStart = antiForgeryInputTag.Replace(@"<input name=""__RequestVerificationToken"" type=""hidden"" value=""", "");
    var tokenValue = removedStart.Replace(@""" />", "");
    if (antiForgeryInputTag == removedStart || removedStart == tokenValue)
        throw new InvalidOperationException("Oops! The Html.AntiForgeryToken() method seems to return something I did not expect.");
    return new MvcHtmlString(string.Format(@"{0}:""{1}""", "__RequestVerificationToken", tokenValue));
}

It will return us a string with AnitforgeryToken value, which we can include in AJAX headers or simply include it in AJAX data (here i Will add it in AJAX data, as we are already getting formatted string like "__RequestVerificationToken:"TokenValue...."")

And use it like below

    $("#submitData").click(function () {
        $.ajax({
            type: 'post',
            url: '/URLHere',
            data: { uname: username,
                    pass: password ,
                    @Html.AntiForgeryTokenForAjaxPost()
                   },
           
        });
    });

OR

Simply generate a AnitForgeryToken in Javascript, and send it with Data

<script type="text/javascript">
    function getGeneratedToken() {
        var token = '@Html.AntiForgeryToken()';
        token = $(token).val();
        return token;
   }
</script>

now while sending AJAX request, add it with data as we did above

$.ajax({
    type: "POST",
    url: "/URLHere",
    data: {
        __RequestVerificationToken: gettoken(),
        uname: username,
        pass: password 
    },
    dataType: 'json',
    contentType: 'application/x-www-form-urlencoded; charset=utf-8'
    
});

The Second approach is basically done using Javascript only, and token is generated on Page load by using Razor Syntax @Html.AntiForgeryToken(), also note the content-type of the above method, it should work if you are posting JSON on server.