I am doing the paper work for my parents's GC application.
Do I need filled out 2 I-864 form for each of them,
-Correct. These are two separate cases. You also need to file two I-130s.
or just copy of one I-864 form?
in the I-864 form, I can check the choice of sponsoring my dad as principal immigrant, and also check the choice of sponsoring my mom as family member.
many thx.