I will review our current knowledge of magnetism in hot stars, in particular the origin and occurrence of magnetic fields in these stars with a radiative envelope, as well as the impact of the magnetic fields on many aspects such as the internal structure of the star, its circumstellar environment, and stellar evolution. These results have been achieved over the last few years thanks to large spectropolarimetric surveys (MiMeS, BinaMIcS, BritePol, LIFE...) combined with theoretical developments and simulations. It is now also possible to combine spectropolarimetry with photometry from space missions (e.g. TESS) to perform magneto-asteroseismology and obtain additional insight on the physics of hot stars