The origin station goes "ok" and the provided documents get scanned in (commercial invoice, waybill). The packages goes along its way. If it is headed to the United States those documents then get transmitted to an office somewhere and someone reviews them and files entry on the shipment with the port it is expected to land in.
Say it's John Smith to Not Huawei Inc and it's 12 phones.
So Customs would get that it's John Smith and such and such street, shipping to Not Huawei Inc at such and such street. They'd then get the tariff number of 8517120050 for cellphones, that the quantity is 12, the country of origin on the docs and the value of the shipment.
What Customs won't see, unless they decide to manually review the commercial invoice themselves, is that the phones were manufactured by Huawei. What Customs and the carrier doen't realize is that "John Smith" is actually "Huawei Employee at Huawei, shipping for Huawei from Huawei to Huawei" because the commercial invoice says John smith to Not Huawei Inc which happens to be a DBA for Huawei (although Customs could catch this via the EIN).
A lot of customs clearance is "If it's written on the commercial invoice, it must be true" unless Customs flags something for manual inspection and decides to question it themselves. And the volume of packages entering the United States is such that it is just impossible to go over even 20% of shipments with a fine-toothed comb. You'd need to drastically increase the number of ports, the size of the ports, probably increase the number of CBP employees doing the job an order of magnitude and you'd still end up slowing down how fast freight is getting moved.
We live in a world where stuff gets on a plane in China and 12 hours later is clearing Customs and getting on a truck to head to it's final sort facility or onto a truck to be delivered to the importer. If you wanted to manually inspect every shipment you'd need an insane amount of warehouse space and something might get released a week or two after landing at the port of entry.