LLCs are considered pass-through entities for the purpose of US taxation; they don’t file taxes in their own right, but have their income reported on the personal income tax returns of their owners. C corporations file their own tax returns. (Somewhat confusingly, C corporations can sometimes elect pass-through status, and LLCs can elect to be taxed like a corporation, but these are not their default treatments.)
Money flowing through an LLC is taxed at the level of the owners of the LLC; money flowing through a corporation is taxed at both the corporate level and additionally when it passes to the owners (either as salary or as a distribution of profits)
