es, there are several note-taking and graphing apps that allow you to access your notes and graphs across multiple devices, including PC, Android phones, and iPhones. Here are a few examples:

1. OneNote: This is a popular note-taking app from Microsoft that allows you to create notes, drawings, and graphs, and access them across multiple devices. OneNote is available for free on Android, iOS, and Windows devices, and you can also access your notes on the web.
2. Evernote: This is another popular note-taking app that allows you to take notes, create to-do lists, and save articles and web pages for later reference. Evernote also allows you to draw and annotate images, and access your notes across multiple devices. Evernote is available for free on Android, iOS, and Windows devices, with premium features available for a monthly subscription.
3. Google Keep: This is a simple note-taking app from Google that allows you to create notes, lists, and reminders, and draw sketches and diagrams. Google Keep is available for free on Android and iOS devices, and you can also access your notes on the web.
4. Notability: This is a powerful note-taking app for iOS devices that allows you to create handwritten notes, annotate PDFs, and draw graphs and diagrams. Notability also allows you to record audio and sync your notes across multiple devices via iCloud.
5. GoodNotes: This is another popular note-taking app for iOS devices that allows you to create handwritten notes and sketches, and annotate PDFs and images. GoodNotes also allows you to draw graphs and diagrams, and sync your notes across multiple devices via iCloud.

All of these apps offer different features and capabilities, so it’s worth trying a few out to see which one works best for your needs.