TAR, short for 'Tape Archive,' is a file archiving format and utility used in Unix and Linux systems. It bundles multiple files and directories into a single archive without compression, preserving the file structure and metadata. TAR is often combined with compression utilities like gzip or bzip2 to create compressed archives, commonly used for data backups and software distribution.

First, create an empty TAR file by constructing the IronTarArchive object. Use the Add method to add multiple files to the TAR file. This method also accepts a directory where all the files in the directory will be added to the output TAR. Finally, use the SaveAs method to export the TAR file.