Press-fit holes are PTH with tighter tolerances than the standard +/-0.10mm. They are used as holes to fit the leads of connectors that will not be soldered but pressed into the holes. To accommodate lead and hole to tightly fit together, the tolerances on both are well defined and more tight than standard. The typical tolerances for the PTH depends on the type of connector that is used and it is the connecter manufacturer who specifies this.
Therefore it is of utmost importance that these tolerances are well defined in your PCB data and that the parameter “Press fit” is checked in the order details.
More info on standard holes to compare with the spec on press fit can be found here