A story has to be 'told' to the reader and a 'narrator' is needed to do this. A narrator's voice can be first, second or third person. Here is a quick summary:
Have a look at the three extracts below. In each case, read through and decide which 'person' each one is written in.
You can check your answers below each extract.
You see, frozen into the ice wall, an ornate trunk open and filled with gold and jewels. You hack away at the ice until you reach the trunk.
Caverns of the Snow Witch by Ian Livingstone
It is written in the second person. The writer is talking directly to you.
Mr Fogg's wardrobe was amply supplied and in the best taste. Each pair of trousers, coat, and vest bore a number, indicating the time of year and season at which they were in turn to be laid out for wearing; and the same system was applied to the master's shoes.
Around the World in Eighty Days by Jules Verne
It is written in the third person. The writer is telling you about Mr Fogg's clothing and how it is arranged.
I continued walking in this manner for some time, endeavouring by bodily exercise to ease the load that weighed upon my mind. I traversed the streets without any clear conception of where I was or what I was doing.
Frankenstein by Mary Shelley
It is written in the first person. The writer is telling the story from the perspective of one of the characters.