To use bits/stdc++.h preprocessor in Visual Studio you need to download the stdc++.h file from the given below link.
Download file from the following link: https://mega.nz/file/feIXkY7a#ECkj1bZKA-72dYzatuKsgBQJ4lMe0v81sfxuhyKCNk0
Create bits folder in the following directory: C:Program Files (x86)Microsoft Visual Studio2019CommunityVCToolsMSVC14.28.29333include
Copy stdc++.h to the bits folder
Restart Visual Studio if it is running and use it