7z is a free, open archive and compressed file format. The development of the format began back in 1999. A compressed archive of the 7z format is created using the special 7-Zip file compression utility, which was created by the programmer Igor Pavlov. This free file archiver has a significant ability to compress data, which makes 7z format files quite popular. Moreover, the size of the archive is practically not limited by anything. Archives in this format can be multi-volume and self-extracting. You can use the encryption option.
RAR is a popular data compression format, it belongs to the category of compressed or archive files. Full name - WinRAR Compressed Archive. The format developer is Eugene Roshal, whose name is part of the original format name (respectively, Roshal ARchiver). It is widely used in the global network, because it has a higher compression ratio compared to similar formats. Most modern archiver programs use the algorithm of this extension. Applicable in Windows, Mac OS and Linux operating systems. A file archive of this format can contain either one or several files (directories).