file extensions

File extensions are the suffixes at the end of a filename, usually consisting of three or four letters following a period (e.g., .txt, .jpg, .pdf). They indicate the type of file and help the operating system determine which programs can open it. For instance, a .jpg extension denotes an image file, while a .pdf represents a document. Understanding file extensions is important for managing files effectively, as it allows users to recognize the format and purpose of the files they are working with. This knowledge helps ensure compatibility and optimal use of software applications.