7-Zip is a file archiver with a high compression ratio and Strong AES-256 encryption in 7z and ZIP formats
7-Zip is free software with open source. The most of the code is under the GNU LGPL license.
You can use 7-Zip on any computer, including a computer in a commercial organization. You don't need to register or pay for 7-Zip.
Download link for 7-zip is https://www.7-zip.org/
Useful video tutorial links for 7-zip are as follows
Installation, use and password protection
How To Download and Install 7-Zip On Windows 10/8/7
Encrypting file folders using 7-Zip
How to password protect files and folders in windows using 7zip
How to download, install and use 7-Zip (Free Archiving Utility)