Microsoft Visio - Formatting Timelines
You can apply the usual formatting techniques, such as themes and variants to a timeline. You can also select a background so that all successive timelines are created using the background template.
For example, in the Design tab, click Borders & Titles to set a professional looking border that includes a title header so that all pages in this timeline have the same background and header information.
It creates a Background page that is overlaid on all other pages in the document.
You can also change the timeline and other shapes to make it look like a block, cylinder, or a bracket by right-clicking the shape and selecting the corresponding type from the menu.