ElIS ???????????

Can someone explain to me what is Elis, who can use it, how do we access it and what type of info can we obtain there. Thank you so much

It's this new thing USCIS is using where you can check your case status, add RFE's, etc. When they send you the receipt letter for your biometrics spot they send a letter with your account to so you can make it online with the access code given but it expired after a certain period of time.