What is the necessity to create a separate file after having an API key?

What is the necessity to create a separate file after having an API key? Correct Answer To hold configuration information

An application programming interface key (API key) is a code passed in by computer programs calling an application programming interface (API) to identify the calling program, its developer, or its user to the Web site. Once you have an API key you should create a separate file to hold all of the configuration information that you will need to share between processes.

Related Questions

You are the administrator of Windows 2000 Server network. On each server you format a separate system partition and a separate boot partition as NTFS. Several months later you shut down one of the computers for maintenance. When you try to restart the computer you receive the following error message "NTLDR is missing, press any key to restart". You want to install a new NTLDR file on the computer but you do not want to loose any settings you made since the installation. What should you do?
What is the necessity to have API?