Go to the official 7-Zip Website to download the extraction tool for free.

A file ending in .7z is a compressed archive created by the open-source software . Users compress files into this format to save disk space and combine multiple files into a single package. How to Safely "Look At" the File

Because file names like this are highly ambiguous, this query could mean a few different things:

It could be a or part of a cybersecurity CTF (Capture The Flag) challenge.