Books are cited in the same way whether they are online or as a hard copy. The author's name is given in full. Book titles should be given in italics and the publisher and date of the publication should be included. The edition should be included (not 1st edition) in the form of '2nd edn' or 'rev edn' for revised edition.
To use a footnote, put a superscript number into your text and then the footnote at the bottom of the page.
Author, Title of book (edition, Publisher Year) Page number referencing.
Timothy Endicott, Administrative Law (4th edn, Oxford University Press 2018) 44.
Author surname initial, Book title (Edition, Publisher Year of Publication)
Endicott, T, Administrative Law (4th edn, Oxford University Press 2018)
The bibliography difference is the author is now listed surname first for the first author, and first initial, you do not include page number(s) and and there is no full stop at the end of the reference.
Pace codes are treated as print titles, each reports shows an ISBN number, and even though you may have viewed it online, if items have ISBNs, the OSCOLA guidance is to treat as a print title.
Home Office, 'Police and Criminal Evidence Act 1984 Code D' (TSO 2017) 31.
With corporate or government agencies authors, in this instance Home Office, the footnote and bibliography entry will look the same, with the exception that a footnote may have a pinpoint page number at the end of the footnote. TSO is the publisher name and stands for The Stationery Office.
Home Office, 'Police and Criminal Evidence Act 1984 Code D' (TSO 2017)