Sporty’s iPad Pilot News has a helpful article about how to connect the new FS2020 to ForeFlight. (You can also find details about using iPads with other PC-based simulations and some ATDs at iPad Pilot News here.)
The process involves using a small utility called Flight Events Client, ensuring that both your iPad and the computer running FS2020 are on the same wifi network, and selecting Flight Events Client as a device in ForeFlight. I have not tested the utility with other EFB apps such as Garmin Pilot.
My tests so far indicate the utility works well, although I did notice that my virtual airplane made occasional jumps into hyperspace before returning to the correct place on the ForeFlight map.
For my initial assessment of using FS2020 to complement flight training and proficiency, see Flight Simulator 2020: First Impressions.