I assume you're not RC or a member of an older protestant church? One of my DDs had a friend in school whose mother, a Baptist, thought Hallowe'en was the devil's birthday and so the friend had nothing to do with it.
Hallowe'en isn't a celebration of evil or witchcraft, despite appearances, and it's not the devil's birthday.
It's the day before the old religious feast, All Saints Day (aka All Hallows Day), 1 November, which is followed the next day by All Souls Day. Hallowe'en means the eve of All Hallows Day.
The Christian feasts were superimposed over the traditional celebration of the end of the harvest and the beginning of the season of darkness. In ancient days it was believed to be a liminal time, when the division between the living and the dead was erased. Customs included wearing of disguises, leaving out food for the spirits of the dead who would visit their old homes, and divining the future.
Over time, these customs morphed into the Hallowe'en we know today. In the intervening time, customs included the carving of turnips, disguises, people going from housebroken house to represent the spirits of the dead, and begging food from households, performing songs, along with various games and customs of divining the future (predicting marriage, wealth, success, etc). An example of this is the Irish barmbrack cake containing a ring, money, a piece of cloth, a thimble and other items. Traditionally in Ireland, bonfires would be lit. These customs are well documented as part of the folk ways of Ireland in the 18th and 19th centuries, and into the 20th.
The customs surrounding Hallowe'en are derived from a mishmash of Christian and older customs associated in Britain and Ireland with the feasts of Samhain and All Hallows, whose importance spread to continental Europe with Irish monks in very early medieval times (around the reign of Charlemagne), then spread to America and eventually England with Irish emigrants.
All Saints Day and All Souls Day are celebrated separately in the RC church, with all Christian dead/ the dead in general commemorated in the CoE, CoI, the Episcopalian Church in the US, and iirc the Lutheran church and some Methodist churches.