The Rede typically refers to two different aspects of the Wiccan Rede, the most common being the eight words, "An it harm none, do what you will." Alternatively, it could refer to what is also known as the long form of the Rede, published in the Green Egg, a magazine for pagans and wiccans in the Spring of 1974, which can be read at: https://en.wikisource.org/wiki/The_Wiccan_Rede
Both versions talk about the ethics Wiccans strive toward as part of their morality.
Archival data indicates a good exegesis on the eight-word version can be found at: https://sacred-texts.com/bos/bos265.htm
A decent history of the Long Rede by Jason Mankey can be found at: https://www.patheos.com/blogs/panmankey/2013/10/redeofthewicca/
For a deeper dive into the origins and wordings, see: https://www.gocek.org/pagan/wiccanredeproject/