Microsoft Visual C++ Redistributable Package contains the run-time components of Visual C++ Libraries needed for running applications on a PC without Visual C++ installed.
Most people will have this installed at some point, being that it is pretty common in many applications and games, explaining why it eventually shows up in most people's programs or apps. In other words, if you don't have a program that needs it, then there is no reason to download this.
Microsoft Visual C++ Redistributable Package comes as a self-installing executable. Download the 32-Bit or 64-Bit version, double click, and follow the prompts.