Traditionally there are three candles on the altar. One for the Maiden, one for the Lord, and one for the Lady.

The Maiden's candle is the central candle on the altar because the Maiden comes before the Lady (i.e. you have to be a girl before you become a woman) and is nearly always white to symbolize her purity.

The Lady's candle represents the Lady, the Goddess of Wicca and is traditionally on the eastern side of the altar, which is also the side that the High Priestess stands. It can be any color depending on what is being celebrated but white is a good all round choice.

The Lord's candle represents the Lord, or God of Wicca and is traditionally on the western side of the altar. Again white is a good all-purpose choice fof color but any color may be used that is significant to the celebration.

Although the candles are all that is actually needed on the altar for representation of the Maiden, Lady and Lord, many practitioners also choose to have a token of some other sort to represent them. Almost anything can be used for this.