Ripping a CD is simply copying music from a audio compact disc (CD) to a computer. FreeRIP is a "ripper" software which is a software that can copy tracks from your CDs and convert them to audio files in various formats, like MP3, Flac, WMA, WAV and Ogg Vorbis.
You may think that a specific software is not needed to do such operation and simply try to drag the audio CD contents, as you see them on the CD folder (usually files with .cda extension), to your hard drive, but unfortunately this will not work (for more details see FAQ How to convert CDA files to MP3).
You really need FreeRIP!
Once you converted your CD to a set of digital audio files (usually one file per track) on your PC hard drive, you can arrange and use them as you like from creating a personal “jukebox” list, to making compilations, to transferring files to portable MP3 players. Nowadays there are many devices that can play audio files, including (but not limited) mobile phones, car stereo, pillows, swiss army knifes, doorbells, digital photo frames, and more! And of course you can play them on your computer while you work or play.