What you want to ask is that all electronic documents have fixed header signature characteristics? Not all electronic documents have fixed title signature characteristics.

Electronic files can have many formats and types, and each format and type will have different header signature characteristics. For example, some common electronic file formats, such as PDF, DOCX, TXT, etc. Both contain a specific byte sequence or metadata in the file header to identify the type and version information of the file. These byte sequences or metadata can be read and parsed to confirm the type and version of the file.

However, there are also some electronic file formats that do not have fixed header signature characteristics, such as plain text files (such as TXT files) or image files (such as JPEG and PNG). ). These files have no specific header signature characteristics, so not all electronic files have fixed header signature characteristics.