According to What’s Filming, which is site that reports on what’s being filmed in Ontario and British Columbia Canada, has officially listed Shazam! to start production in February of 2018 until May of the same year, in Toronto, Canada.
Toronto is also the same city that Suicide Squad was filmed in, in 2015.
In the listing, What’s Filming has Shazam! production code name being as “Franklin”, going along with all the other production code names for the other DC Extended Universe films, such as Wonder Woman being named “Nightingale”, Suicide Squad having “Bravo 14” and Batman v Superman: Dawn of Justice having “Sage and Milo”.
As of now, Warner Bros. hasn’t officially announced what actors are attached to Shazam!, all we know is that David F. Sandberg (Annabelle: Creation) is attached to direct and Henry Gayden (Earth to Echo) has written the script for the film.