For ansys R2022 is available. But i think for the new version R2024 we should introduce it and i cant find how.
You can do it in CFD Post but you will have to define an expression for the speed of sound in the "Expressions" tab. i.e something like c = sqrt(gamma*R*Temperature) and then M = Velocity/c. You would be able to plot "M" after doing that.
c = sqrt(gamma*R*Temperature)
M = Velocity/c
If you use Fluent for post processing then the expressions are not needed.