In fact this is a defualt wayputer OS shows the file names. And its very practical. E.g. a document may be of a .doc italic (old Word format) . docx italic (Word xml format) . rtf italic (rich format) .odt (open document ) or many other document formats. Without knowing the actual format you may not be able to provide your collaborators with a proper file (Word 219 recognises the Open Document Format older versions don). The file name extension allows you to distniguish between the different files with the same name such as italic and its PDF version italic It also shows it may not be a good idea to use more than one full stop (the one between the name and the extension) in a file name. You can hide the extensions by setting the respective flag - for W see below for macOS by selecting Finder all filename extensions. If you run a directory listingmand (ls on Mac Linux) from themand line you alway see the full name.