Hi Golam, eligibility criteria are institution specific. The basic requirements are you being financially capable to meet the course fees and living/travel expenses. Medical Certificate (including HIV/AIDS Test) from a renowned Medical Practitioner and average percentage in your school and/or UG. For scholarships, candidates who score 60% above in 12th Standard/Bachelor Degree are usually eligible for a scholarship test or highest marks (distinction) are considered if no test is involved.
You need to score a 93 for the internet-based exam and 580 for the paper-based exam for TOEFL and 6.5 are required with a minimum score of 6.0 in each component of the academic IELTS. In regards to GRE you need to score 90% and above.