Angel Healing is a quasi-religious alternative therapy involving someone who claims they are able to channel angels by guiding supposed healing powers over a person in need of healing. The person receiving therapy lies still whilst the practitioner gently rests their hands on the affected areas to guide the angels to do their stuff. Many people would find it relaxing to be gently touched by strangers but there is little evidence that angels even exist, let alone have healing powers to respond to every request of an aching knee or stiff neck.
Practitioners will claim there are different angels in the 'spiritual realm', all having different healing powers and personalities. It is difficult to pin down any other specific practices or concepts unique to Angel Healing, as they are often bound up with other pseudoscientific modalities such as reiki, crystal therapy and the like.
It goes without saying that there is absolutely no evidence for any of their claims.