The method developed by Mikao Usui spread over the world. Though controversial, correspondence courses over the internet even offer distant training. To achieve a complete education in the "Usui method of Reiki Healing", 3 courses are necessary: the 1st degree course, the 2nd degree course and the master course. The specific contents of each of these courses vary widely from one teacher to another, depending on personal philosophies. A typical set of courses is something like the following.

1st degree Reiki courses teach the basic theories of how to work with Reiki energy. The channel through which Reiki energy passes to the 7th chakra is said to be widened through an initiation by the teacher, to let the Reiki energy be strong enough to heal. Students learn the manner in which to place their hands on the body of the recipient said to be most successful in the healing process.

In the 2nd degree Reiki course, a symbol for mental healing is purportedly taught, training students to say that they can treat even deeply ingrained problems like fears, depression, addictions and the like. It is also taught how to supposedly direct the energy to a certain point in time, to a specific person or place or a specific issue. The issue can be something like a particular health problem of an individual, or it can be a more abstract or general issue such as world peace. Practitioners say that this is possible using three symbols taught at the second initiation. The claim is that this skill allows the channel to be opened even wider.

As part of the master course, usually the third degree, students become a Reiki "master" through the third initiation; they learn how to initiate students and have the option of teaching Reiki courses themselves. The student learns a further "master" level symbol in this course as well as the method of attuning others. In some case the third level is broken into smaller stages of attunements from the teacher, as well as being taught the attunements for the first second and third level in stages. A teacher has completed practical training when told he or she has the ability to attune others to all degrees and has been given the final fourth Reiki Master symbol that is used in attunements.

The first and second stages can also be broken up into smaller levels of attunements and received symbols, however this is very rarely done and teachers often do not know how to do this. It is generally found to be impractical so is not widely practiced, taught or known.

It is up to students how many levels they want to complete. The courses are sequential, and can be expensive, especially the third (master) level. Often a teacher will require time in between one course and another (time in which the student is expected to apply new learning before taking the next degree). Before offering Reiki treatments to the public, a student is often advised to take a second-degree course.