Absolutely! You have the option to save your notes at the subtopic level. To do this, simply make use of the Notes function located in the top right corner of the toolbar. It's represented by a dedicated icon.
Please note that it's not possible to enter notes at the Topic level. However, you can easily access and review all the notes you've entered in the corresponding subtopics from the Topic level.
Kindly be aware that images cannot be included in your notes.