You can edit the location of your user bar by going to Appearance > Styles > XenForo - UI.X > Style Property Groups > [UI.X] User/Mod bar and using the User Bar Location drop down menu.
The height of the user bar can be adjusted by entering your preferred height in pixels within the User Bar Height. If you'd the height of the sticky user bar to differ, enter a different height in the Sticky User Bar Height in pixels. To turn off the sticky user bar, uncheck Sticky User Bar.