Do you like to draw? It is a visual art that can use various drawing instruments.
I do like to draw, but I am horrible at it.  I mainly use a pencil.
You can use pencils, pens, wax colored pencils, crayons, charcoal, chalk, pastels, or markers. I love using oil pastels.
Have you been trained in art or is it just a hobby for you?
It is just a hobby. I love how it is such a simple way to communicate visual ideas.
Those visual ideas are up to interpretation though, right?  Not everyone will look at it the same way.
True. It just depends on what is being communicated. Drawing is a popular means of public expression.