What do you mean by "promoting the design of plane materials"?

Promoting graphic design is to publicize graphic design materials. For example: CD covers, posters, company stationery, envelopes, bookmarks, etc.

Graphic design, also known as visual communication design, takes "vision" as a way of communication and expression, and creates and combines symbols, pictures and words in various ways to make a visual expression to convey ideas or information. Graphic designers may use professional skills, such as typesetting, visual arts, page layout and computer software, to achieve the purpose of creative planning. Graphic design can usually refer to the process of making (designing) and the final finished work.

Common uses of graphic design include logos (trademarks and brands), publications (magazines, newspapers and books), print advertisements, posters, billboards, graphic elements of websites, logos and product packaging. For example, product packaging may include trademarks or other works of art, arranged texts and pure design elements, such as images, shapes, sizes and colors with uniform styles. Combination is one of the most important features of graphic design, especially when the product uses pre-existing materials or multiple elements.