Here are the list of items:

1) Copy I-20(Not required)

2) Letter  from University-  verified that  you are graduating on ---

4) Invitation letter from  you  to  your parents.(Not required)

5)  Copy  of Passport( first two pages only) and  Visa

Thats  all from you, your parents might need to submit following

1) Property Documents  verified from CA.

2) Letter  from his/her job stating that him/her approved for vaccation for---period.

3) Bank Statement

4) Relationship certified from  VDC OR NAGARPALIKA  OFICE.