eBooks are cited simliar to print books. It is not necessary to include the ebook format. If the book has a DOI or non-database URL this should be included too.
Example from an academic database:
Winters, A. (2014). The displaced of capital. University of Chicago Press.
Example with DOI or non-database URL:
Brown, L.S. (2018). Feminist therapy (2nd ed.). American Psychological Association. https://doi.org/10.1037/0000092-000
Since the page number of ebooks are not consistent (i.e. they change depending on the device and font settings) you should not use page numbers for in-text citations. One option is to use paragraph numbers if they are provided. (You can also manually count the paragraphs if you wish.)
Winters describes the a summer thunderstorm noting how "the first drops strike their light civic stripes on the pavement" (para. 2).
It is okay to use page numbers in a pdf version of an ebook where the page numbers are consistent with the print version.