Christian fiction - some books overtly express elements of Christianity in the story, integrating things like prayer, conversion, and church. Other books don’t include overt references to Christianity but they are written from a Christian worldview, adhering to Biblical principles and usually expressing some aspect of redemption, God’s unconditional love, or honest grappling with faith. Christian fiction can have non-Christian elements, but they can’t be without consequence or some kind of opinion that comes through in the prose. If your story features exotic dancers (read: strippers), it can’t glorify their lifestyle or make it look like it’s a value-neutral activity. In general, you want your story populated with real people who struggle with real-life issues; and you also want to reflect an effort for believers to live in ways that glorify God.
Christian non-fiction is usually overt in its use of Biblical principles to teach a particular subject. For example, I’ve received quite a few queries about leadership books. The Bible contains numerous teachings that apply to leadership, so for us to represent a leadership book, it would need to contain specific Biblical tenets. When we consider a memoir, it’s usually a person’s faith journey and their wrestling with the spiritual side of life, perhaps about another life issue such as an illness or an addiction.