Shareboxed
File safety on a Mac is four habits, and they protect against different things. Doing them in order matters, because the flashy one people start with is the least likely disaster.
1. Turn on FileVault
FileVault encrypts the whole disk, so a stolen or lost MacBook is a brick instead of a data breach. On Apple silicon it costs nothing noticeable in speed. System Settings, Privacy and Security, FileVault, on. Store the recovery key somewhere that is not the same laptop. This is ten minutes and it covers the most common physical risk.
2. Back up like you mean it
Encryption protects against theft; backups protect against everything else, which is most things: dead SSDs, spilled coffee, your own delete key. Time Machine to a disk at home is the floor. The ceiling is the 3-2-1 shape: three copies, two kinds of storage, one of them somewhere else. An encrypted cloud backup or a disk at a friend's house both count as somewhere else.
3. Share without making copies you cannot take back
Most real-world leaks are not hackers; they are files handed out and never un-handed. An attachment lives in someone's inbox forever. A cloud drive link works until you remember to close it. Safer sharing means links that end: encrypted before they leave your Mac, expiring on their own, with a password sent through a different channel. That is the problem Shareboxed exists to solve, and the password post explains what the password actually protects.
4. Guard the keys, not just the files
Everything above sits behind your passwords. Use the built-in Passwords app or a password manager, turn on two-factor for your Apple account and email, and prefer passkeys where a service offers them; they cannot be phished or reused. Your email account deserves the most care of all, because it can reset everything else.
What you can skip
Antivirus subscriptions rarely earn their keep on a modern Mac; Gatekeeper and XProtect already refuse unsigned and known-bad software. The honest threats are a lost laptop, a dead disk and a link that never expired. The four habits above cover exactly those three.