The Encrypting File System (EFS) is the built-in encryption tool in Windows 10, which is used to encrypt files and folders on NTFS drives to protect them from unwanted access.
This is the strongest protection that is available in Windows to support you to keep your individual files and folders secure
This video you learn, how to use Encrypting File System (EFS) in files and folders.
One is good idea I use in the video. After watching, you are able to know how encryption keys are generated and use in other location.
Cipher : How to Encrypt and Decrypt Files and Folders in Windows 10