Add this button to each page-layout that your app is using. (side not: Best-practice is to have only one page-layout and remove all the others). Likely this is Atlas_Default in Atlas_Core->Web->Responsive->Layouts.
So if you want to copy this from the Workflow page: open that page in StudioPro, go to the pages properties, find the layout name. Open the layout (Ctrl-G) and copy-paste their logic to your page-layouts.
HI Tim, Yes I know I can create custom layout and add a sign out button then use this for my pages, but the Workflow pages will still be using the Atlas_default and not my custom. In the Approval template the Workflow pages also has the logout button but they did not change the Atlas_Default (they did not add any button there) nor do they have any custom that they changed the workflow to, it is as if that logout button appears there by magic. How did they do that? In the meantime I have already created my own custom atlas_default_WithLogotu page, and also duplicateing the Workflow pages to use this layout, that is the only way I can see, but that is not what they did and I want to knwo how they did that without changing the Atlas_Default, there must be something I am missing.
I am blind, I checked the Approval template again and there is a fodler “User” under which there are “Pages” and there is a copy of the workflow “TaskInbox” page and then it references a custom layout “Approvals_TopBar”, so that is how they did it as well, that is how I have implemented it, then that is confirmed the correct and only way.