Files with the WLL extension are known as Microsoft Word Add-Ins. Microsoft Word is compatible with multiple operating systems and currently one of the top applications for creating and editing text documents.

Word documents contain various elements such as images, drawn objects, tables, links to websites and to other local files and also feature a wide variety of text formatting options and styles.
Add-Ins provide additional features to Word documents such as easy to use mathematical symbols, drop-down menus or chemical symbols. Some Add-Ins are available as soon as the program is installed.

How to open WLL files

Add-Ins have to be installed on the computer before they can be used. After the installation process is completed, the Add-Ins need to be loaded into Word. If an Add-In is not available automatically, it can be added manually to the Add-Ins list by browsing to the location of the WLL file and selecting it.