the symbolical meaning in the colour of candles?
each colour has multiple meaning, so it would be better reading up colour correspondences in magick. white can be substituted for any colour because it is seen as a combination of all colours, but white is typically used for purification, or to represent the Goddess in circle.
I also want to know what other colours of candles stand for.
again, look it up yourself because there's many meaning [the link bellow should help you] also keep in mind colour correspondences can change with your culture [like eastern cultures wear white at funerals while western cultures wear black] as well as your own personal practice [pink is usually associated with love, but i know people who work with chakras and use green for love spells]
white candle is use for purify something or erase something
yes, they can be used to purify a space. they can also be used to protect a space. and some people will place a white candle in the window to welcome spirits. it all depends on your energy and intent, but you can use a white candle to purify.