For iOS, you can use the Files app to long-press and share the archive with an unzipping utility. Android users can find dedicated RAR extractors on the Google Play Store.
A RAR (Roshal Archive) is a proprietary format that compresses multiple files into a single, smaller package to save storage space and speed up internet transfers. They are often used for: Need to open, create, or convert a RAR file? - WinZip Hangman_Vdo_Preview_05.rar
If the extraction fails, it may be due to a corrupted file from an incomplete download or a filename that is too long for your operating system to handle. What is a RAR File? For iOS, you can use the Files app