Each text element can have default enter and exit animations assigned to it. The default animations are show when the text is created or when it is animated from script.
In order to set up default animations add the GlyphAnimator component to your 3D Text :
You can now drag and drop any SimpleAnimation object as an Insert/Delete animation. You can find a handful of ready made SimpleAnimation objects in the Animation Presets folder.
You can select the animation time and mode.
Now the text can be easily animated from script.