You just need to use Html.fromHtml() to use HTML in your XML Strings.
Note: If you are simply referencing a String with HTML in your layout XML, it will not work.
Try using the code given below:
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
textView.setText(Html.fromHtml("<h2>Title</h2><br><p>Description here</p>", Html.FROM_HTML_MODE_COMPACT));
} else {
textView.setText(Html.fromHtml("<h2>Title</h2><br><p>Description here</p>"));
}