While the majority of transgender men who take testosterone are able to obtain the deeper voices that they seek, some instead turn to voice training or surgery to make the voice more masculine.

Healthline - Everything You Need to Know About Voice Masculinization
icliniq - Voice Masculinization Surgery - An Overview
John Hopkins Medicine - Transgender and Gender-Diverse Voice Care
Mayo Clinic - Gender-affirming (transgender) voice therapy and surgery
Mirror Review - What to Expect During Voice Masculinization Surgery Recovery
Professional Voice - Masculinization Laryngoplasty