Excuse me, what is the red seal circled in white on the plaque in the picture below? What is the collective name? For example: call the head cover? Or fingerprints?

This is the so-called introduction chapter.

The first chapter is a chapter printed in the upper right corner of calligraphy works, also known as "conformal chapter", which is carved out of the shape of stone. Generally, it should not be square, but translucent, rectangular, circular, semi-circular, conformal gourd-shaped, natural and shaw-shaped. Whether to quote the first chapter of calligraphy works depends on the need. If the first paragraph is too neat, it needs to be "deformed"; The seal at the end of the paragraph is too heavy and needs to be "upgraded"; The distribution of seals on the works is monotonous and needs to be "adjusted". At this time, we should consider the first chapter.

Generally, the first chapter is called Zhai Haozhang and Elegant Chapter. The most used chapter should be Yazhang.