How do I deepen my voice (I'm a female) to sound like a man in a video for a school project?
I know some audio software that does a good job:


Audacity (free software) - effect -> change pitch (set the pitch to down, lower down the semi-tones and the percent change)
Adobe Audition (paid software) - there is a plugin called pitch shifter (lower down a little bit the semi-tones and cents)


Both are audio software which means you will need to export your audio from the video clip and because there are other people talking in the video you will need to select the parts only were you are talking and then apply the effect.