Is it permissible to enroll in free educational programs (such as language and sewing classes) offered by a church in America, knowing that they provide all supplies at their own expense?

There is no objection to accepting assistance from a non-Muslim for a Muslim, nor to acquiring beneficial knowledge from them, provided there is no fear of temptation (fitna). Therefore, there is no objection for the questioner to benefit from the service program affiliated with the church, provided there is no fear of temptation, and that it is not accompanied by a religious prohibition or becomes a cause for inclination of the heart towards them and their affection.