According to USPTO “the drawing disclosure is the most important element of the application”. Furthermore, there are 7 standard views including Perspective, Front, Back, Top, Bottom, Left and Right view required for best practices. It may be including more/less than 7 figures as per requirement accordingly.

When an invention can be illustrated by way of a drawing, the patent laws require that a patent applicant submit at least one patent drawing (also known as a patent illustration). In other words, you need at least one patent drawing whenever a drawing will make an invention easier to grasp. My experience has shown me that patent drawings are nearly always necessary, and that include a lot of them will make your application stronger and better.

Simply when the invention relates to a chemical component or composition is being claimed, or only a technique or procedure is being claimed, are patent drawings not necessary. Nevertheless, almost every technique or procedure can be shown in some manner, shape, or form. In light of this, it would be prudent for applicants to offer examples even when a method is being asserted.