They want non-fiction prose and poetry. They have detailed guidelines as well as several suggested topics for each theme. Two of their upcoming themes are:
-- Stories about November & December holidays: (“Please submit your true stories about the entire December holiday season, including Thanksgiving, Christmas, Hanukkah, Kwanzaa, Boxing Day, and New Year's festivities too. Remember that these holiday titles do make wonderful gifts for everyone on your list!”). Deadline: 1 May 2026 
-- Miracles, messages from heaven & angels (“We are now accepting stories for another book about unexplained happenings and occurrences. Stories about miracles, angels, messages from heaven, premonitions, amazing coincidences and other unexplainable but good events! … We are looking for powerful, astounding, stories that will make people say "wow" or give them chills. This book is for everyone, whether religious or non-religious.”). Deadline: 15 May 2026
They have other themes listed too, with later deadlines. Chicken Soup for the Soul pays $250 for works up to 1,200 words. Details here and here (also see other tabs on this page, including FAQ).