８老師, can I e-file H4?

８老師,

    For H4 petition, can I do e-file? I checked the list which you recommended to me. Should I convert all the documents into PDF file and upload them? Do I get the confirmation of reception from USCIS immediately right after I finish document transfering online? If that is true, is it considered to be "received by USCIS"? 

    I do hear that some people like to do certified-mail. Which way is better (in terms of timing)?

    Thanks a lot!