1) The horizontal configuration is the preferred one.
2) The cloud-only configuration is for use as a UI icon, when the text of our name can't be reproduced due to tiny size, or when the name is already displayed in text.
Usually our logo is displayed in our Zscaler Blue color on a white background
Other times our logo is shown in white on a background of our Zscaler Blue color. (Keep in mind that white logos are only visible after you place them on top of solid backgrounds.)