Motion is companion software for FCPX, and enables you to customise/build titles and other elements which you can then access as menu options in FCPX.
An especially useful tool is the ability to get the software to analyse movement of objects within a frame and to make greenscreened/keyed layers match that movement - for example, a phone or TV screen.
The Motion interface can be daunting if you haven't used anything like it before, but as ever there are lots of great free (and paid-for options) guides online, such as this...
...
