Legal guardianship question

[Rueb]

I have a sister whom I am sending to college, both my parents are deceased, I am about to file my I-140 but I want to include my sister since she is a dependend, how do I go about getting a legal document that I can also include on filing my I-140 to show that she is my depended or do I even need to do that?. Please advise. I am in possession of the death certificates of my parents, will that be enough?. My sister is 19 and she is a full time student and she is on a F??visa

 

[EricS]

I have a sister whom I am sending to college, both my parents are deceased, I am about to file my I-140 but I want to include my sister since she is a dependend, how do I go about getting a legal document that I can also include on filing my I-140 to show that she is my depended or do I even need to do that?. Please advise. I am in possession of the death certificates of my parents, will that be enough?. My sister is 19 and she is a full time student and she is on a F??visa

As per my knowledge, dependents are not included in 140 filing.
Your sister will be considered your dependent for GC purpose or not is a seperate question though.