A citation for an electronic book is the same as citing a print book. However, when citing an eBook in MLA style, the core element Title of Container becomes important as well as the Location which is the URL or DOI (Digital Object Identifier).
Note: While MLA recommends including full URLs, follow your professor's instructions.
Examples of various ebooks which are read online are given below.
WC: Wolf, Kenneth Baker. The Poverty of Riches: St. Francis of Assisi Reconsidered. Oxford UP, 2005. Ebscohost eBooks, www.netLibrary.com/urlapi.asp?action=summary&v=1&bookid=138272.
For ebooks with page numbers, the parenthetical, in-text citation will be just like a print book.
P: (Wolf 45)
When citing an item freely available on the internet, such as Google Books, use Google Books or other named ebook archive as the container title followed by the URL.
WD: Habermas, Gary. The Historical Jesus: Ancient Evidence for the Life of Christ. College Press, 1996. Google Books, books.google.com/books?id=pMMeqKHZIDkC&lpg=PP1&dq=historical%20Jesus&pg=PP1#v=onepage&q&f=false.
P. (Habermas 56)
A downloaded ebook read on a personal device, such as a kindle book, is considered a version and should be treated as such. If you do not know the specific ereader version, simply state e-book.
WC: Wright, N. T. Small Faith---Great God. Kindle ed., InterVarsity Press, 2010.
When specific page numbers or other exact location identifiers are not available, use another numbered section such as chapters as shown below. MLA states to place a comma after the author name and abbreviate the section type.
P: (Wright, ch. 2)