form of expression; mode of presentation
Refers to the concrete shape, medium, or style in which something is expressed or presented, such as a literary genre, artistic format, or communication method.
This writer is exploring new forms of expression.
I tried changing the presentation format.
表現方法 is more about the method or technique of expression, while 表現形式 emphasizes the concrete form or format.
Compound of 表現 (expression) and 形式 (form, format).