1. What is a RAR file
RAR is the native format of WinRAR archiver. Like other archives, RAR files are data containers, they store one or several files in the compressed form. After you downloaded RAR file from Internet, you need to unpack its contents in order to use it.
2. How to handle RAR files
WinRAR provides the complete support for RAR files, so you may
both create and unpack them. If you installed WinRAR on your computer
and downloaded RAR file from Internet, you may double click on RAR file
icon to open it in WinRAR, select all files, press "Extract To"
button, enter a destination path and press "OK".
Another way is to click on the RAR file in Explorer using the right mouse
button. If you enabled "Shell integration" option when installing WinRAR,
the file context menu will contain "Extract to ..." item.
3. RAR versus ZIP
Comparing to ZIP file format, RAR provides a number of advanced features: more convenient multipart (multivolume) archives, tight compression including the special solid mode, strong AES-256 encryption, recovery records to repair an archive even in case of physical data damage, Unicode support to process non-English file names and a lot more.