I always wonder where do sopranos, alto, and tenor practice their vocal, so that there do not disturb their neighbours? Especially those who are taking examinations like the ABRSM, Trinity, etc. I live in apartmemt and I'm really curious about the answers.
Do you know your neighbors? If not go meet them, talk to them, and work something out. Maybe they can't even hear you. Maybe they can but don't mind.
Give them your phone number, tell them to call if they are ever bothered and you will stop. This gives them a chance to tell you if they are sick, or need to work, or need quiet for any reason.
Also ask if there are any times that are bad. Maybe they have a kid that naps at a certain time, or go to bed early on one night of the week.
It may also be good to find out your local noise ordinance times so you are not violating them. This will at the very least keep the police from visiting.
I played in a band in college and we rented the first floor of a house and practiced in the basement. We had upstairs neighbors. When new neighbors moved in we met them and did what I said above and they said "Listen, you don't call the cops when we have parties and we don't care when you practice." It worked out really well. We would have practice, they would party, the party would spill into the basement and we gained a lot of fans that would then come to our gigs.
Bottom line is get to know your neighbors and it may work out fine.
If you have to ask, I assume you are not studying at a music school because you'd have access to practice rooms. There are still a few options.
If you are studying somewhere,chances are it has a music room (if it's a high school), or a music department (if it's a college). All jokes we instrumentalists make about vocalists aside (we make them because we can't sing ;), chances are the instructors and students will be sympathetic to your cause and let you practice there.
Many recording studious offer rehearsal space. People tend to think about Abbey Road or something when they think about recording studios, but in fact they come in all sizes and shapes, and many are a lot cheaper than you may think. Since you need no gear or help from the audio engineers to practice, you can go for the cheapest. You may be able to get an even better deal if you can come at odd hours.
And then there's the sneaky option. If you have connections at some music school, you may be able to sneak into an unused practice room, especially at hours of least demand for them. I know people who have done that, including one person who simply walked into a random music school with his instument, asked the staff if it's ok to take an unused practice room, and got an affirmative answer.
I practise in the car, on the motorway. No reading, of course ;) but I have playlists on the phone/carplay specifically for routining.
Those lucky enough to afford or be donated rehearsal space would probably use that, with or without tracks, though I kind of like to not be singing in silence.
I do occasionally do vocal work in my own workroom - but I am quite aware of the fact I can be heard through the entirety of my own building & half of next door's too. I do it when I need to, rather than just when I want to.