Helium is used extensively throughout the Apollo/Saturn V space vehicle for a number of applications. The welding use is not discussed since it is a special topic. In the first stage (S-IC), helium is used for liquid oxygen tank pressurization during vehicle checkout and launch.
One of the orange Aid Preprint Series in Nuclear Astrophysics by W. B. Hubbard, California Institute of Technology, Pasadena, California.; Argues that the Saturnian models are flawed as their predictions do not line up with detected gravitational events.