.rar is a common archive file format that typically holds multiple files, compressed to save space.
Based on the text "otomi-games.com_M0SIYVW4.rar", this appears to be a compressed file archive associated with the website otomi-games.com.
You will need a file compression utility, such as WinRAR or 7-Zip , to extract the contents of this file.
If you can tell me, I can help you with extraction, finding the source, or getting the password.