Catholics light candles during official church services (called liturgy, such as Mass) to indicate the special solemnity of the occasion. Perhaps you are also referring to those stands which have small banks of candles which people can light (usually within small glass containers, colored or not, and often called "vigil lights"). Often you can find them near a statue or icon of Mary. These are called votive candles and indicate that someone is praying about something particular, either for themselves or on behalf of someone else. The word "votive" can also refer to a promise to pray for someone, as well as a wish or desire for a certain outcome on behalf of someone, such as recovery of health. Jesus said that he was the Light of the world and told his followers that you are the Light of the world. Jesus came to shine a Light in a dark and sin filled world. His Light was Truth exposing the sin that hid in the darkness. Jesus instructed his followers to shine their Light and show the world the Truth in them also so that others would know they belonged to God as an example to those others.
Most Catholics light candles when praying for the dead, including monks if they have them available in their monastery.
Some (such as Roman Catholics do), some light them during special seasons such as Advent, and in some candles are it as the service starts.
Hanukkah is one holiday in which you would light candles.
They light candles.
a match
They had candles to light rooms.
White candles reflect the light in the experiment.
There are only eight candles on the menorah; plus a ninth which is used to light the other candles.
Typically, candles are lit for light or for religious or spiritual purposes.
Candles are used to make light.
about 4 candles can light up a bed area
Unless you have a dog that is trained to light candles, I would recommend that people do it.