Note taking applications
I use a lot of file upload apps, some are good and some are plain terrible. From the most popular I was using the Dropbox, Google Drive, GNotes, Color Notes, Google Keep and Evernote. There are some others but they are not so good, at least not in my opinion.
If you are uploading somewhere, upload it to a reliable website, otherwise you could lose your content.
Dropbox is fast and reliable and you can share file by file, the whole folder and connect it to the multiple messengers and online services, like Fotolia.
Google Drive is reliable too, but slow, annoying and a little bit complicated. But, you can do all kind of the things with Drive, including programming and building forms.
GNotes was one of my favorite web-based and Android note-taking application, but from time to time they have glitches, but the overall impression is good. I think it is cute, so I was using it.
ColorNotes is an all-android note-taking app, no photo upload, you can make checklists and notes with alarms and reminders. It's fast, lightweight and you can cross copy, share HTML, use it for reading and for lots of things.
Google Keep is a very good app, with tags serving as folders, you can attach photos and the overall impression is very very beautiful and eye-pleasing screen. Colors are way too bright for my taste.
Evernote is a robust application, with the endless possibilities. Recommended for the cutting edge professionals, plus it gives an opportunity to host a blog through the Postach.io.
Security for an each is different, but so far I think these are solid to use.