Why would the strum be called the V? This has to do with the form your fingers take whenever playing this strum. By placing your thumb across and between the first and second knuckle of the index finger, this forms a V type shape. The positioning of the fingers is important for the successful execution of this strum. Take a look at the demonstration video below:
Where do we use this? This can be used when you wish, but to start off try to use it in the progression of I – IV – V on the I. Then you can use it on the I – IV and then finally with all of them or I – IV – V. Try it in the key of your choice.