You must meet 3 fundamental requirements in order to receive masters education in the United States:
A Strong Academic Background
You must have at least 4-year university degree. Although the importance of it varies based on the school the grade point average is usually an criterion.
Sufficient Financial Resources
You must be able to demostrate that you can cover your education and life expenses in the United States either by yourself or through another resource.
You must have a decent level of English proficiency fto be accepted for masters level education.