7-Zip, like WinZip, creates a container called an archive that holds the files to be protected. That archive can be encrypted and protected with a password. 7Zip is free software that creates Zip files that can open with WinZip, WinRAR, or similar programs.
The compression ratio results depend heavily on the data used for the tests. Usually, 7Zip compresses to 7z format 30-70% better than to zip format, and it compresses to zip format 2-10% better than most other zip-compatible programs.
The program 7-Zip (AKA 7Zip) can be used in three ways: from its graphical user interface (the most popular), a command-line interface, or as a shell integration. The default 7z file format offers one of the highest compression ratios (using LZMA and LZMA2—Lempel–Ziv–Markov chain algorithm, an algorithm used for lossless data compression); that's why this app is probably the most popular free file archiver.