Assuming 12.6 is Audio Studio (AS) , I do not think the legacy (Direct X) Wave Hammer plug-in was included with AS... neither is the new Wave Hammer II (which does not have sought-after FET 1176 vintage sound) . If you have a version of SF Pro installed, Wave Hammer may be listed in the Direct X, All or Third-Party plug-ins. Look in organize or the Fx chainer FWIW, in AS-15, it is listed as "Magix Wave Hammer, but it is totally missing in AS-16. In fact. there are no third-party plug-ins available at all in AS-16. I do not know if this is by design or by mistake. Otherwise there are other many compressor/limiters and volume maximizers available (free or otherwise).
btw, welcome to the Magix Sound Forge users community @j-Drinda.
I wonder if there's another achieving the same result with iZotope or some free VST Apps?
I am not aware of any that sound the same as the legacy Wave Hammer. Otherwise there are more comp-limiter-maximixers than I can count that are available for free or otherwise. The free and easy to use LoudMax is popular, but it does not sound like WH. I use TDR's 'Limiter No 6' sometimes, which has five stages of comp-limiting, but it does not sound like WH either and may be confusing to non-audio folks,