One is obligated to light two candles before Yom Kippur with the following two blessings: 1) Ba-ruch A-tah A-do-nai E-lo-hei-nu Me-lech ha-olam a-sher ki-deshanu be-mitz-vo-tav ve-tzvi-va-nu le-had-lik ner shel Yom Ha-Ki-pu-rim. 2) Ba-ruch A-tah Ado-nai E-lo-hei-nu Me-lech ha-o-lam she-he-che-ya-nu ve-ki-yi-ma-nu ve-hi-gi-ya-nu liz-man ha-zeh.
If one plans on driving to shul after lighting, one should state out loud that they are not accepting the holiness of the day through lighting the candles. They should also omit the 2nd blessing (shehechiyanu) and should say it in shul with the congregation.
In addition to the regular holiday candles, a Yahrtzeit candle should be lit for those who say Yizkor. (One candle may be lit for all deceased family members.)
A 25 hour candle should be lit from which to make Havdallah on after Yom Kippur.
Some have a custom to light an additional candle for the household.