In the US, each state has its own rules of vehicle registration. There is no such thing as ‘US license plates’ as they vary from state to state. In most cases, the vehicle numbers begin with letters and continue with digits. The total number of symbols is usually 4-5 in small states and 6-7 in large ones. Apart from the number, the license plate may contain the address of vehicle registration.
There is much variety to the license plate series in the US. There also are series where all symbols follow each other directly, without breaks. The first symbol is always a letter; the second may be a letter or number. You can learn more about a particular series by looking up the first two symbols.
Usually registration number is pressed on the plastin. Some states prefer flat numbers which is printed with paint. In early times license numbers were just painted but it was dangerous because of bandits. They could do the fake. In case of pressed number to do a fake will be difficult.