what do I write in no 4 alien registrtaion no?
-If you look at the any USCIS receipt you received previously, you might be having Alien Number that starts with A-XXXXXXXXX.

No 5 uscis Elis account no?
-The USCIS Electronic Immigration System (USCIS ELIS) is an online, account-based system that allows you to submit and view certain benefit requests, receive electronic notification of decisions, and receive real-time case status updates.
So you might not be having this number. but you can use the I-94 number here.

6 us socila security no? I dont have social security no.
-If you are in F1 and didnot have work authorization, or didnot work in college and did not apply for Social Security number, you might not be having this too.


25 (b)date authorized period of stay ? because my visa is expired already but i have I20 with validity
-Use I-20 valid until Date here if mentioned, otherwise D/S. (called duration of stay). This is usually in I-94 issued for F1 (F1 Approval receipt from USCIS)

While filing 765 for EAD, use C19 not A12.

good luck.