Both vocal technique and training are essential for a singer. However, good vocal technique should be the basis. Even if you already have a good voice, a qualified voice teacher will help you develop your voice even further. And a vocal coach will make sure you're ready to perform.
It's one of those contradictory things. If it turns out that you have many advantages that make singing quite natural, such as a good ear, a lot of musical exposure as a child, and a good sense of your own voice and body, then it may seem easy to learn to sing without formal instruction. When you have a session with such a coach, you would normally have to bring a pianist and work almost exclusively on the repertoire and not necessarily on the concepts of voice construction. Adam Mishan is a YouTube vocal coach with hundreds of thousands of subscribers and has personally trained hundreds of students to improve their voices.
HOWEVER, if you are not able to take classes right now, I recommend that you closely imitate vocalists of all genres, which can help you learn a lot of things. Although they may have the same goals for you, a vocal coach is usually a pianist, which means there is no reason for him to give you a full voice lesson. Tension, fatigue and vocal cord injuries, including vocal ganglia (calluses on the vocal cords due to overuse or misuse), vocal cord polyps and vocal cord cysts are the injuries that most singers suffer As a vocal coach, I know many technical concepts, and I can identify what a singer is doing to produce a sound or if the sound is correct or not, but that doesn't mean that I want to go deeper into these technical concepts. However, others of us don't have the option of paying for a coach, either because of a lack of vocal coaches in our area or because we simply don't have the financial capacity to pay for classes.
In addition to a voice teacher, an excellent vocal coach who understands where you are coming from and where you are going is essential for any singer trying to have a career. The only concern here, of course, is to make sure that the vocalist you're imitating sings healthily. Other benefits of learning with a vocal coach are improvements in vocal tone, range and freedom, as well as consistency in vocal quality and, therefore, confidence in the voice. With proper vocal technique and proper vocal care, the concern of damaging the voice will significantly decrease.
This means someone with a deep understanding of vocal technique and who knows how to communicate it in a way that you can understand. In addition, good teachers will impart science-based information to their students and offer practical solutions to their vocal problems so that they can continue to apply the techniques after they have finished classes. Some people have grown up singing all their lives, while others have the option of paying for a vocal coach. These are deep questions and difficult decisions, but the most important reasons to be with a teacher are to make healthy vocal improvements, solve problems, and maintain a beneficial vocal technique.
I've only had 6 singing lessons in my life, but I've learned a lot of tips and tricks in those lessons that have greatly improved my singing.