Right-click the file and select "Extract here." Be aware that many .7z archives of this nature are password-protected to prevent automated scanners from seeing what's inside.
Files named with hashes like this typically appear in a few specific scenarios: d4ac4633ebd6440fa397b84f1bc94a3c.7z
Many servers rename files to their hash values to prevent naming conflicts and to ensure that the file hasn't been corrupted during download. Right-click the file and select "Extract here
When you encounter a file with a name as cryptic as d4ac4633ebd6440fa397b84f1bc94a3c.7z , caution is your best friend. Since the filename is obfuscated, there is no way to know if it contains a harmless document or malicious software without opening it—which you should do if you didn't expect to receive it. d4ac4633ebd6440fa397b84f1bc94a3c.7z