The Transcendental Argument for God is often treated as a singular argument for God but it is more so a type of argument the same way cosmological arguments and ontological arguments are types of arguments. They have been popularized in recent times by presuppositional apologists such as Van Til, Clark, and Bahnsen, but transcendental arguments for God can be seen prior in some of the works of the idealists including the transcendental idealist Immanuel Kant (The Only Possible Argument… Kant 1763) and the Absolute Idealist Josiah Royce (The Religious Aspect of Philosophy, Royce 1885). The form of the argument is as such:

1. God is the necessary precondition for X
2. X
3. Therefore God exists

It's important to note that transcendental arguments have been made for things other than God, but for our intents and purposes we will focus our attention on arguments for God. X varies depending on the particular argument being made. Some substitutions for X include knowledge, existence, values, error, predication, logic, language, thought mathematics, possibility, an external world, etc. This is not an exhaustive list.

Notes: Transcendental Arguments (Stroud 1968), I have read this paper a couple times and will provide Stroud's argument against the structure and form all transcendental arguments which entails the transcendental arguments for God.