Want to change (to increase\reduce\remove) formants (in vocal)

By formants, I understand the following: region of amplified partial tones in voice sound spectrum. Or another definition: In acoustics, a formant is usually defined as a broad peak, or local maximum, in the spectrum.

My purpuse is to listen voice with changed formants.

I think that’s a bit too specialist for a general purpose audio tool like Audacity.
I’d suggest that you look at specialist voice analysis software, such as Praat.

(There’s a good description of formants here: https://person2.sol.lu.se/SidneyWood/praate/whatform.html)