The app should allow the user to import pdfs into notebooks, export notebooks as pdf, have more colors available for the pen, have the "crayon" and "fountain pen" types of writing, allow you to enter text from keyboard, allow you to insert images, make ruler and protractor available, allow you to insert bookmarks and allow you to filter the pages of a notebook according to a category entered by the user. To be at the top, the app should allow you to copy/paste the written text and should allow you to create more subgroups for the notebooks so as to be more orderly.