This is a general guideline of documents that are usually required, each program may be different, make sure to check the requirements.
- TOEFL or IELTS
- GRE (General and/or Subject)
- Statement of Purpose
- Resume (including past research experiences, publications, work experiences, etc.)
- Recommendation Letters
A holistic application: Most universities in the US and Canada have holistic admissions, which means the admissions officers consider the whole applicant, not just empirical data like one’s GPA, or English exam scores.
So if your GPA is low, don’t worry, they look at everything in your application, you can make up for it with publications, a compelling Statement of Purpose, etc.