What is csrss.exe Process in Windows? Is it a Virus? How to Identify Orignal file?

People ask me mostly about different Windows processes and now trying to answer one by one, let’s see the csrss process, What is csrss.exe? What is the process file location? How to identify the original and viruses and how to remove csrss without a tool. The csrss.exe is a Client Server Runtime Subsystem process file, [...]