The possibilities to change an Element or Page is usually limited for an end user but you can change size and color for an Element or Page. See Personalizing Lobby Pages.
Elements used in the Context Pane may be reordered. The width of elements may also be customized. See Using Lobby Elements in the Context Pane.
There are also tools for creating Elements (Element Designer), creating Data Sources that retrieve data from IFS Applications (Data Source Designer) and creating Lobby Pages (Page Designer).
To created and change Elements, Data Sources and Lobby pages you need the Lobby Designers package. Read more in the Technical documentation under IFS Administration & Configuration Guide/User Interface/Lobby.