If you mean a small notebook:
* Carnet: This is the most common and versatile word for a notebook, regardless of size.
* Cahier: This is another common word for a notebook, but it usually refers to a larger, bound notebook with lined pages.
* Bloc-notes: This specifically refers to a notepad, often with sticky notes.
* Petit carnet: This literally means "small notebook" and can be used for a jotter.
If you mean someone who jots down notes:
* Preneur de notes: This literally means "note taker" and can be used for someone who jots down notes.
* Secrétaire: This can be used for someone who takes minutes or notes in a meeting.
* Noteux: This is a less common word for someone who takes notes.
Ultimately, the best word to use will depend on the specific context.