The U.S. uses it
There are four candles on the outside of the Advent wreath. There is one pink candle and three purple candles.
They do it among others in Germany and Denmark
Four, they represent the four Sundays of Advent.
An advent wreath normally contains four candles, three violet for penance, and one rose candle for joy, that is for the third Sunday of Advent.
The Advent Wreath was originally a Lutheran tradition which marks the four weeks of Advent. Made of evergreen branches layed horizontally, is had four candles representing the weeks. We use the Advent Wreath today but it is refered to as a Christmas wreath.
Four candles, three purple, one pink.
All candles are sacramentals used in the Church's liturgy. The candles particular to Advent would be the candles on the Advent wreath, and these stand for the four Sundays in Advent, which is focused on penance and preparation for the coming of the Lord, both in His Nativity and in His Second Coming.
The first candle is lit on the first Sunday of Advent. Each succeeding Sunday an additional candle is lit until all four are lit on the forth Sunday of Advent.
Advent is the four Sundays before Christmas. My church has an "advent wreath" with five candles (one for each of the Sundays of advent and one for Christmas eve).
To set up an advent wreath, place a wreath on a flat surface and insert four candles evenly spaced around the wreath. Light one candle each Sunday leading up to Christmas, starting with the first candle on the first Sunday of Advent.
To make an advent wreath, gather a wreath base, four candles (three purple and one pink), greenery, and decorations. Attach the candles to the wreath, with three on one side and one on the other. Light one candle each Sunday leading up to Christmas. Decorate the wreath with greenery and other items as desired.
To create an advent wreath, start with a circular wreath base and place four candles evenly around it. Light one candle each Sunday leading up to Christmas. Decorate the wreath with greenery and other symbols of the season.