The most common argument employed will be a “transcendental argument” – an argument which deals with the preconditions for the intelligibility of human experience. You will most typically see the “Transcendental Argument for the existence of God”, or TAG, employed for this purpose. As a whole, however, Presuppositionalism is an argument on the worldview level; and per the Christian worldview, there are two worldviews – Christianity, and not-Christianity. The denial of Christianity necessitates the affirmation of it’s antithesis, or it’s opposite.
As such, we deal with concepts such as “The impossibility of the contrary”, or “internal critique”, which serve to demonstrate that the contrary position does not provide the preconditions for intelligibility, by it’s own standards. Put in simple terms, the denial of Christianity is itself a worldview; but not a worldview which can account for human experience, reality, or anything else. This lack of an account for such things renders the worldview impossible to consistently hold. Further, it involves the “borrowing” of elements of the Christian worldview, in order to make its objections, or its claims in the first place.
The argument stated in several forms:
“The transcendental proof for God’s existence is that without Him it is impossible to prove anything.”
Premise 1A: “If knowledge then God”
Premise 2A: “knowledge”
Conclusion A: “therefore God”
X presupposes CT;