I’ve done a lot of canning, there are two types of pressure cookers - one with a gauge and one that uses a weight that ‘rocks’ when it reaches a certain measurement of pressure depending on the size of vent.
In both cases the pressure is adjusted up or down by heat adjustment.
I use one with a gauge, that also has a vent hole with a weight that rocks at 15lbs psi.
It’s important to remember that altitude changes the pressure needed:)