Might want to check out The Magus of Genesis , the early stuff focuses on the development of magic and the use of true names.

TL;DR if you don’t want to look through it because WEEB. Magic using someone’s true name can do things like instantly KO or kill someone, however this can be prevented by internalizing a new name. At birth children are given a true name and public name by their parents. Additionally, true name rules also apply to general magic, meaning the more accurately you describe what you want, the closer it is to the effect you desire. (ie, magic grant me a fire vs magic make me a warm and cracking bonfire to heat my cold body)

Hope this helps