Question: how to apply for green card for your parents?
Answer: Step 1: File an immigration petition for beneficiary (i.e. your parents). File Form I-130 for each parent. ... 
Step 2: Complete Form G-325A, Biographical Information. ... 
Step 3: Complete Form I-864 Affidavit of support by sponsor (you) for your parents. ... 
Step 4: Medical exam and Form I-693.