Soap is made by the reaction between fatty acids, that can be oils extracted from plants or animal fat, and an alkali.
In the case of avocado soap, usually a mixture of vegetable oils is used with avocado oil forming a large part in addition to other oils like olive oil which are gentle on the skin.
To make the soap, a mixture of the oil to be used is created and heated to around 100 degree Fahrenheit. The alkali solution is created by dissolving sodium hydroxide or potassium hydroxide crystals in water. The alkali solution is then mixed with the oil and stirred continuously.
The alkali reacts with the fatty acids when mixed to form a salt which is the soap that we require. This can be set by placing it in a mould and allowing it to harden.