I resolved by putting this code in OnLoadResource() method instead of OnPageFinished() and using evaluateJavascript:

override fun onLoadResource(view: WebView?, url: String?) {
        webView.evaluateJavascript("javascript:(function() { " +
                "var head = document.getElementsByTagName('footer')[0];"
                + "head.parentNode.removeChild(head);" +
                "})()", {});
    }

I used this code and working but it first loads with website header and then afterward loads without header.
What is wrong in this code? What to modify so that only one screen loads, i.e, without website header?

webSettings.setJavaScriptEnabled(true);

webView.setWebViewClient(new WebViewClient()
{
    @Override
    public void onPageFinished(WebView view, String url)
    {
        webView.loadUrl("javascript:(function() { " +
                "var head = document.getElementsByTagName('header')[0];"
                + "head.parentNode.removeChild(head);" +
                "})()");

        webView.loadUrl("javascript:(function() { " +
                "var head = document.getElementsByTagName('footer')[0];"
                + "head.parentNode.removeChild(head);" +
                "})()");
    }
});

webView.loadUrl("https://www.google.com");