what is the thing a candle holds?
A candle holds itself. There is a wick inside, if that is what you mean.
Are you referring to what holds a candle?
A candleholder.
The thing a candle holds is called a "candlestick" or a "candle holder." It is a device designed to support and hold a candle in an upright position while it burns. Candlesticks come in various shapes, sizes, and materials, ranging from simple metal or glass holders to more elaborate and decorative designs.
If you want to find out more about candlesticks, you can search for images or descriptions online. Simply enter "candlestick" or "candle holder" into a search engine, and you will be able to see different types of candlesticks and learn more about their history and uses.