My H1 Petition Got Filed on May 16 and not received my petition number yet

My Friends whose petitions got filed after may 16th have received petition numbers already. Will USCIS process the petitions randomly or sequentially ? will they not process the petitions in order ?

I presume they process the petitions sequentially on a weekly basis (week-by-week).

USCIS had a [press release]( in May which suggests that there could be a delay in sending out the receipt notices to the peitioners and you should expect your receipt notice to be send out by mid-July.