A descrption of Geoff Johns' planned Shazam! comic book title has been found over at the writer's new company website.
"A new series coming in fall 2018! Billy Batson and his surrogate family; Mary Bromfield, Freddy Freeman, Darla Dudley, Eugen Choi and Pedro Pena unlock the mysteries of the Rock of Eternity and delve into the secret worlds of magic to discover their ultimate destiny!"
That would appear to continue the story from Johns and artist Gary Frank's Shazam! back-up serial which ran in the writer's Justice League run during "New 52." That story is the basis for New Line Cinema's upcoming Shazam! film.