Because you can’t see your singing voice, you need some tools to help you make changes. One way to obtain these tools is to make sure that your lesson involves work with a variety of techniques, such as imagery.
The teacher may use images to help you understand how to make the best sounds. The teacher may ask you to notice the sensations as you sing, give you something to visualize as you sing, or give you something to listen for. All three approaches can work beautifully for you as you work on your voice.
You may also find that one approach works best for you. Knowing your preferred approach is good because you can translate what your teacher says into your own language. For instance, if your teacher describes something to you and explains the anatomy of why that worked, you may remember what it felt like when you made the best sounds.
If you enjoy working with images, you can find a way to visualize the sound to enhance your experience.
Don’t fret if a teacher wants to explain physically what’s happening. You may not want to know in the beginning, but later you may be glad that you understand why a particular image works.