A WDZ file is a compressed archive created by WDZip, a tool included in WINDEV used to compress and decompress files into archives. It contains one or more files of the same or different formats. WDZ files are used to group and compress files to organize multiple files and save space.

WDZip can be used to create archives in several different formats. The default format the program uses is the WDZ format, but it can also save in the .ZIP, .RAR, .CAB, and .7Z formats. To create an archive in WDZip, select "WDZIP" in the "Utilities" group, which is located in the "Tools" pane. Then, click "New" or select File → New archive..., and choose the format of the archive. When creating an archive, you may choose to split it into several sub-archives if it is a large archive. These sub-archives can be merged together when opening the archive. If you split a WDZ archive, the first sub-archive is a WDZ file and the next sub-archive is a .001 file, then a .002 file, and so on. To open an archive in WDZip, select File → Open an archive. You can then extract or delete one or more files in the archive.