To "put together" (create) or open (extract) a .rar file, you need specialized software because Windows and macOS do not natively support RAR creation.
Highlight the files or folders you want to compress.
A command-line utility used to test and extract archives. 2. How to "Put Together" (Create) a RAR File
If your goal is to bundle files into a new archive named TEST.rar : Download and install the application.