On average approximately 80-85 new graduate students are admitted to Christ Church each year; some of these will have completed an undergraduate degree at Christ Church, but the majority come from elsewhere, including many from overseas.
Please see Christ Church's listing on the University website: https://www.ox.ac.uk/admissions/graduate/colleges/christ-church for information including details of the courses for which Christ Church admits students.
Please also see https://www.ox.ac.uk/admissions/graduate, which provides essential information for prospective graduates including the application guide and contact details for the University's Graduate Admissions Office.