I'm 17 (M) And It seems like I cannot get a deeper voice for some reason. Puberty did me the MOST dirty and BARELY did anything to my voice. And...

Seek a lower vibration. Practice. Humm

• Relax your vocal cords, lower intonation is a more open throated expression. More air, more open. If you take singing classes they teach you that kind of stuff.

• Masculine isn’t necessarily a pitch, although deeper is interpreted as more masculine in context.

• Know where you fit and expand what you’ve got. Try imitating others, and don’t constrict your throat trying to sound deep.

• Try thinking of it like you’re yawning while talking.

• I recommend starting with YouTube and channels like Trans Voice Lessons' older videos.

• Relax your jaw, shoulders and throat muscles. Feel your throat opening up and your larynx descending. It helps to yawn.
  Now spend a few minutes every day - or as often as you like - humming in that state, going as low as is comfortable, then just a bit lower. Don't force it, and don't try to power through any pain, because that'll make your voice tense and high. You can get a tone generating app, and harmonise to a frequency, lowering it carefully.

• You could, however, try to talk better in general. Not pushing for a deeper voice, but for a more relaxed tone. Speaking with more confidence and enunciation. That can actually help you overall in the long run

Give yourself a 30-day challenge. As you watch your recordings, look for areas where your body language, facial gestures, and tone can improve. Find spots in your responses where you can slow down or pause in order to drive a point home. The difference between the first take and your 20th will astound you.

• Pace
• Power (from your belly)
• Pause
• Depth
• Inflection (not AT people)

https://www.youtube.com/watch?v=lCufGjD1oQs