Traditional animation is mainly dealing with drawing by hand on paper. It may also be called 2D animation. Most techniques can be applied to digital animation as well. It can take a short or long period of time whether doing full animation or limited animation. Full animation takes longer because animators work on a high-quality motion picture. Limited animation is less time consuming animators put less detail on the animation. Drawing background, props, characters on transparent pieces of paper can speed the process of the project. After the drawings are complete and in sequential order, every drawing is photographed. Rotoscoping is a technique in traditional animation where animators trace and draw an real life action sequence or picture. It is used to create more realistic scenes.
There aren't apps or software for drawing on paper. On the other hand traditional aniamtion is also used in digital animation where there are many apps and software. To edit, add music, and add some effects to your project you can use apps such Powerdirector, Imovie, and/or clips. Software like DaVinci Resolve 12.5, Shotcut Video Editor, and/or Adobe After Effects.
Any camera or smart phone can be used to photograph the drawings.
Pablo Navarro Demo Reel 2006 by Pablo Navarro on Youtube.
Jordan Krahn's demo reel by Jordan Krahn on Youtube.
1st place winner (2d traditional animation) By Paola Delgado on Youtube.