A document can have any acceptable WIn95 file name.
The name cannot contain any of these characters: * ? \ / : | < >. Also, the file names should not contain characters that have special meanings on other platforms, such as $ and #. Avoid using DOS command names as file names.
The name is followed by an optional period and an extension one to three characters long, which indicates the type of file. The program uses .tex for documents, .bak for backup filesBackup_files.tex, .rap for wrapped filesWrapped_files.tex, and .shl for shell documents. If you do not specify an extension, the program adds .tex automatically. Regardless of the extension, all documents are saved as LaTeX files. If you specify a different extension, you must include it every time you type the file name.