Look online for singing lessons. If you want to learn in person (which I'd recommend) search for teachers in your area. Most have at least a modest amount of local or online advertising. You can also checkout craigslist or ask on a local subreddit.
I found my singing teacher through a Google search, and I found my violin teacher through word of mouth.
My girlfriend is an opera singer and voice teacher who's pivoting to primarily online lessons. She's working on establishing an online presence and is offering free consultations and promotional rates. If you're interested, email me at the address in my profile. She has substantial experience teaching people with technical backgrounds (such as me) and is fluent in communicating concepts accordingly. I'd suggest at least the consultation so she can guide you in the right direction, if anything!
My wife is a singing teacher and has been trained by these guys for a long time. The education and training has been a very high standard. As always your millage will vary depending on the teacher you choose and their level of experience.
I have a neighbor who's a professional opera singer and gives voice lessons. From what I hear, most of his opera colleagues do as well. If you live in a city with an opera company, it might be worth checking with them.
(Personally, I've taken up beginner piano with him this year!)
