Reiki is a system of energy transference. It can be used for healing.
I have done both
western lineage (Dr. Chujiro Hayashi/Hawayo Takata/Dr. Barbara Weber Ray, Beth Gray and Phyllis Furumoto) and
eastern lineage (Dr. Chujiro Hayashi/Chiyoko Yamaguchi/Tadao Yamaguchi), I prefer the eastern lineage (Jikiden) as a method of working, but the most common is the western lineage.
Investigate both and see which you would prefer.
If you can find Reiki exchange groups, do join them as it will enhance your experience. I often use Reiki in place of meditation - and pets love it, too.
Cheers,
Webwitch