Do you want the text to be magically appearing or do you want a pen to be writing it?
In either case, you're talking about using After Effects to create the write-on part.
You can either make the text appear completely in After Effects (after you render out of Cinema4D and import your project into AE). Or you can create your paper texture (in Photoshop?) animate the writing on happening in After Effects and use the resulting video as a texture in Cinema 4D.
- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')
No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.