When you say drawing, this means that you are just making different marks on a surface. There are different types of items that you can use in order to draw. For example, you may want to draw with the use of a pen, or you may draw with the use of a pencil.
It will depend on you, which item you will use so that you can continue drawing. When you say sketch, this may refer to doing some marks first that is temporary because you are going to make further changes to them to make them more permanent. There are instances when sketches will not have all of the details that a finished drawing may have.
Sketching and drawing are generally interchangeable, as both have their place in art and business. Sketching is a freehand drawing that depends on lines and shading, preferably with only a pencil. It usually lacks detail, but it also invites a suggestion.
For an artist, the sketch serves as a material that will be used later on. Drawing, on the other hand, has more specifics, and it is created with an assortment of different utensils, including crayons, pastel, markers, and pencils. With a drawing, the lines are neater and more precise. Drawings typically have more color for better impact