The best apps for processing RAW are the Adobe apps: Photoshop, Elements or Lightroom. They all use the same Adobe Camera RAW plugin, although a few features are "crippled" in the "Elements" version (things like batch processing).
But, in most cases, RAW will be pretty useless on the Note 5, or any other phone. With the tiny sensor that phones have, not much useful data is saved in RAW, as the pixels are SO small. Also, noise reduction isn't applied in a RAW image - and there is a LOT of noise on small-sensor images, although you can do noise processing on a RAW image. Good noise processing, however, often requires a separate post-processing program or plugin.
I don't have my Note 5 yet, so haven't tested it, but don't have a lot of hope that RAW will be much use.