People are generally OK with the idea of having various important documents stored their Mac, and are quite happy with the existing protecti built into macOS, including using FileVault to encrypt drives and even simply have a password to access the user account in the first place.
However, some users may find that some elements are too important or private to not apply an extra level of security. This can range from the need to secure professial records that need to be sent to another user, to additial protecti of birth certificates and passports, to keep embarrassing childhood pictures out of sight of other members of the family who sometimes even borrow user account.
e soluti is to use Disk Utility to create an encrypted, password-protected disk image.

Creati of the image
Opening of the disk utility
In the Disk Utility menu
A new dialog box will appear with a number of optis available to create the file …