https://www.freechristianebooks.org/
Several websites offer free Christian ebooks that you can link to on your website. CCEL.org, GlobalChristians.org, and ChristianBook.com are good starting points, offering a variety of free titles, according to musicaltheologian.com, GlobalChristians.Org, and christianworldview.net. You can find classic works, modern resources, and even Bible studies.