Hi @Amalia.sari
I'm the beneficiary and glad knowing there is Indonesian too here. My fiance sent the package on April 25th and we got our NOA 1 on April 30th. So I suppose they have received your petition too. Did your fiance attach form G-1145? So that he will receive text/email when USCIS has received your package.
It sounds like your fiance, the petitioner, is in the US, is this correct? If so, ask him to call USCIS (800-375-5283). Follow the prompts to check the status of the case, and there's an option to press if you don't know your case number.
I definitely recommend getting organized with this stuff. Make copies of everything. This is definitely not the process to be misplacing things, so get a good personal filing system in place or else the road ahead could be rough.