The online application form for graduate study at Oxford you will submit and the documents you need to provide for the academic assessment of your application are the same regardless of whether you are from the UK, EU or outside the EU.
However, for many students applying from outside the UK and/or whose first language is not English, it will also be necessary to provide recent scores from a standardised test of English proficiency recognised by the University, such as IELTS or TOEFL, in order to demonstrate that you have the necessary skills and confidence in academic English to successfully engage with your programme at Oxford.
Some students will need a visa in order to study in the UK. The level of fees you will pay and the funding options available to you will also vary depending on factors related to your nationality and your country of legal permanent residence.
In addition to the standard information on the Graduate Admissions website, students from outside the UK should read the Guidance for International Students to make sure that they are familiar with the English proficiency requirement, and other parts of the admissions process which are particularly important to international students.