Built into Audacity are two equalizers, Filter Curve and Graphic EQ.

The first 4 frequencies are not audible by human beings, the last 4 only just …
https ://en.wikipedia.org/wiki/Human_hearing_range#Humans

If by “hz” you meant kHz, the first 4 are audible by most people, but the last 4 only by dogs & bats.

That doesn’t really make sense. If your question has not been answered, try rephrasing it, and / or describe what you are actually trying to do.