My understanding is that with fractional reserve banking, a bank in that system can create money through loaning money.
There are some limits on a given bank because it needs to keep a "fractional reserve" but money is being created during the loan process.
This money may initially a blip on a computer screen, but those blips can be converted to paper bills, if desired.
My understanding is that regional or local banks cannot print US dollars but they can create money. If people or businesses pay that money back with interest, then the bank has a larger asset base from which to make larger loans.
This ability for money to be created throughout the banking system can lead to a situation where there is more and more money in the system. If not checked, this can lead to instability.
I have heard the phrase "government currencies eventually become worthless." This may be related to the fact that it is tempting to create more and more money to meet current needs and then eventually the system crashes. People in political office often like to put problems off into the future, rather than deal with them in a given current term. I think that the US currency and economy may have been designed to crash. In volatile markets, is one understands what is happening, it is possible to make money in both upswings and downswings. More fundamentally, the conditions for "crash by system design" may have been implemented as an attempted societal control mechanism.