Documentation details:
Page title: Using the view's UI | ArcGIS API for JavaScript 4.4
Page URL: https://developers.arcgis.com/javascript/latest/sample-code/simple-ui/index.html
The same Code create on error by me HTML Site.
For the Logo Code must have :
var logo = domConstruct.create("img", {
src: "https://placeholdit.imgix.net/~text?bg=000&txtclr=e8117f&txtsize=48&txt=logo&w=100&h=80",
id: "logo",
title: "logo"
});
view.ui.add(logo, "bottom-right");
Ist this Right?