Since the Charter of Rights is not an independent enactment, it is cited as Part I of the Constitution Act, 1982.
General Citation for the Charter of Rights and Freedoms
Canadian Charter of Rights and Freedoms, s 7, Part 1 of the Constitution Act, 1982, being Schedule B to the Canada Act 1982 (UK), 1982, c 11.
"Note that pinpoint references to the Canadian Charter and the Constitution Act, 1982 are immediately after the title. For any other constitutional statutes, place pinpoint references after the chapter number." (Canadian Guide to Uniform Legal Citation, 9th ed., p. E-27)
Citation with Section #
Note the unusual placement of the Charter section number (section 15) in the following example:
Canadian Charter of Rights and Freedoms, s 15, Part 1 of the Constitution Act, 1982, being Schedule B to the Canada Act 1982 (UK), 1982, c 11.
The section number (s #) will change depending on what part of the Charter of Rights and Freedoms you are looking at.
Citation from the print version:
Canadian Charter of Rights and Freedoms, s 15, Part I of the Constitution Act, 1982, being Schedule B to the Canada Act 1982 (UK), 1982, c 11.
Citation from an online database (Quicklaw):
Canadian Charter of Rights and Freedoms, s 15, Part I of the Constitution Act, 1982, being Schedule B to the Canada Act 1982 (UK), 1982, c 11, (QL).