When your voice sounds terrible on audio (???)

[iGM]

Right now, I'm using my laptop. However I wanna take the entire audio file, and be able to make a tweak to the tone. For raw audio files as well as videos I use HitFilm.

Okay thats the issue.
To record decent audio, you need a decent quality microphone to capture it. No amount of tweaking can make up for a bad, raw audio file recording.
In terms of editing the audio file, look into Audacity. It is a free audio recording and editing suite withe plenty of YouTube tutorials. Try looking for Pitch Adjustment tutorials - that controls how high or low the audio file frequencies are.