It depends on the kind of music they do. Opera singers –absolutely. You can't sing this kind of music without formal training and lots of it! Most Broadway singers also tend to be trained singers because show tunes can also be vocally challenging and they would be required to sing a heavy schedule of rehearsals and performances.

Pop singers, rock singers, etc. Not necessarily. Why learn to sing when there's autotune? To be fair, there are many, many talented singers in more popular, non-classical types of music. However, if they do take lessons, it is usually in an attempt to preserve the voice they have rather than change or necessarily improve upon it.
Metal singers are famous for their "screams" but to literally scream night after night would ruin their vocal cords in a very short time–there is a way to "scream" that is actually physically safer and more musically appealing.

Sometimes singers will go to a vocal coach or teacher after they have experienced career threatening vocal problems that require medical intervention to fix. To avoid future problems, they may decide to seek the help of the best coach they can find that specializes in their sort of music.

While people in classical types of music freely admit to training, rock and pop stars seem to want their fans to believe all their talent is completely "natural". They might have started taking piano lessons when they were toddlers but now expect you to believe they can't even read sheet music.

Amateur singers will believe they too can practice their way to greatness without a lick of help from anyone. However those amateurs are the ones who overlook the fact that some people really are born with more musical ability than others. If you can't even carry a tune and have a soft whispery voice and limited range, practicing in front of your bathroom mirror won't turn you into Freddie Mercury.

To find out if individual singers have had musical training or not, you can easily google for biographical information. It'll tell you whether or not they took lessons or went to a performing arts school, or sought the advice of a famous singing teacher.

Wow. How I wish my mother did the same when I was young lol.
Hello Eric, you can go to Artists Academy, they have a good reputation in music lessons for young children.
A lot of my neighbors also bring their little ones to this school.

Enjoy.

I am not a voice teacher, and I certainly hope for your sake at least a couple of voice teachers see your question and tell you to stop trying to train yourself before you injure your voice yourself!

You obviously care a great deal about your voice and your singing, so please find the best teacher you can possibly get on your budget. Don't think you can't afford lessons without at least looking and asking around. Fees vary a lot, and you really can't afford not to find a qualified voice instructor that can help you develop the full potential of your voice.

And about that voice. To use operatic terms for non-operatic singing is silly. Other than general voice designations like soprano, tenor, etc. They really don't apply. Even in opera, different designations may apply more to operatic roles than operatic voices. A singer may be better at one type of role than another, but often you'll find a coloratura soprano doing a lyric soprano role or vice versa. To quote one website on operatic fachs: "No two opera singers are alike. Each voice has its own timbre, its own range, its own good features, and its own limitations" Http://www.helium.com/items/120760-an-ex…

Don't label yourself before your voice is adequately trained under the careful supervision and guidance of a voice teacher! Why limit yourself at this point? Furthermore like many novice singers, you seem to be obsessed with obtaining high notes mistakenly believing that to sing really high indicates a singer's talent rather than a natural ability. Some singers can reach extremely high registers with no help at all, some with much training, and others not at all. Small children can without the slightest difficulty reach a C6 and beyond. Have you ever heard a toddler screech in the middle of a store when being denied a toy or sweet? Don't neglect the rest of your register! Actually learn to sing! A prime example is Adam Lopez who broke the world record for the highest note hit by a male. First clip is him setting the record, the second clip is him actually singing but straining or off pitch on notes in a regular tenor range.
Http://www.youtube.com/watch?v=Kdp4NHWr7…
Http://www.youtube.com/watch?v=uabPjhy9J…

Your focus should be to sing with as beautiful a tone as you possibly can. If you actually do plan to sing opera, then proper vocal training–years of it–is not an option! I'm an amateur singer who did have a few years of formal training in college (I was an English major, not a voice student), but after several years of not singing any type of classical music at all, I found myself heading back into voice lessons so I could sing choral music and participate in amateur opera and musical theatre without blowing out my vocal cords. Care of your instrument–your voice–can be a lifelong process. It's nothing that can be done by slapping some label on yourself before you even know what you are capable of singing.

Below are some helpful information for you on voice types, but this is to clarify any confusion. It is not a substitute for formal study. Meanwhile sing only what is comfortable for you to sing. Never force your voice!