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 Studio\2019\Community\VC\Tools\MSVC\14.28.29333\include
Copy stdc++.h to the bits folder
Restart Visual Studio if it is running and use it