Your feed rate is based on the RPM of the tool and the lead of your tap. You have 3 ways to set the lead of your thread. TPI = threads per inch ie 3/4-16 where 16 would be your TPI. MMPR = millimeter per revolution ie M14 x 2 where 2 would be your MMPR, And IPR = inches per revolution 3/4-16 where .0625 would be IPR. The actual feed rate that is output on your G-code is based on your RPM. For instance, with a 3/4-16 tap if you have an RPM of 500, the feed rate would be F31.25 IPM. If the RPM was 725 the feed rate would be F45.3125 IPM.
Of course when you run the .NCL file through your post processor it is up to that as to how your feed rate is output to your G-code program. Some machines want the feed rate in IPM (inches per minute) where other ones want it as FPR (feed per revolution) The way that outputs is totally dependent on the post processor program and not CREO.