No I-94, What To Put?

[Statusrebel]

Wife entered the US on a Visa Waiver Program through an online ESTA application.

So she doesn't have an I-94 / I-94W card in her passport.

So when asked the I-94# on AOS form (and other forms), which she doesn't have, shall she enter the ESTA application number or put n/a?

Thank you so much for your help.

[immihelp]

If she entered on ESTA, how can she file I-485 (AOS)?