"Reflexology is a form of massage that focuses on healing and helping different parts of the body via the feet and hands"
Reflexology is one of those words that gets thrown around a lot in a lot of different ways. Sometimes it is billed as a mystical type of massage practiced only by those from the "far east", sometimes sold as a "DIY" type of massage, and even very firmly warned against in pregnancy for fears of "causing premature labor" (Which is completely untrue, by the way). However Reflexology is promoted, it basically states the same thing: Spots/points/or conditions in your body can be affected in a good way by pressing on certain spots or points in your feet as well as the hands.
There is not a lot of definitive history as to where Reflexology originated. Egyptian hieroglyphics found in the tomb of Ankmahor who was known as a "physician of high esteem", show massage focused on the feet. Texts and images from Ancient China show therapy using the hands and feet. North American Native Americans practiced a form of Zone Therapy in which pressure was put on certain parts of the feet and hands to help heal pain and illness. Physicians across Europe, Asia, and the Americas studied all of these different histories, combining other forms of therapy such as acupressure and physiotherapy to develop a what is today known as Reflexology.
In Reflexology, it is believed that the whole body, it's organs, and systems are connected to and reflected in the feet as well as the hands, and even on the face and ears. To have an effect on an organ or part of the body, a specific spot is pressed with static pressure for 3-5 seconds. Different combinations of pressure on different points can help those areas work together to relieve the issue. The top of the foot contains areas at the top of the body and so on downward. For example, if someone has trouble with their sinuses, pressure can be applied to the tips of the toes or fingers to try and relieve the pain and clear it up. Reflexology can be used to help a number of issues from chronic pain, to just maintaining overall health and well-being. There are points to have an effect on not just major organs, but also smaller glands that when worked on may help hormone production issues, helping provide balance and relief from people suffering from things like thyroid conditions, fertility issues, or relieving pain and overproduction of stress hormones like adrenaline and cortisol.
Like many forms of "alternative" massage and therapies, some believe in it's qualities, and others don't. There are constantly ongoing research studies using modern technologies to try and determine if working on pressure points does anything. In the meantime, Reflexology is a gentle form of massage that can potentially have strong effects on parts of the body that otherwise wouldn't wouldn't be able to have manual therapy done to it.