This article explains what a CSV file is and the best methods I have used to open, edit, and convert a CSV file.
Opening .CSV Files with Excel – Quick Tip on Delimited Text Files
A CSV file is a comma-separated values file. It is a plain text file that can only contain numbers and letters and structures the data in it into a table format.
Files that end with the CSV file extension are generally used to exchange data, usually if there is a large amount of it, between different applications. Database programs, analytics software, and other applications that store huge amounts of information (such as contact and customer data) usually support this format.
A comma separated values file is sometimes also called a character separated values file or a comma separated values file, but whatever you call it, it is always the same format.