Ways to keep your information safe on Mac
To protect the information on your Mac, perform regular backups, limit access to your information, install software updates, take precautions to find or deactivate a lost computer, and avoid malware.
Perform regular backups
You should always back up your Mac. That way, if something happens to your Mac or you accidentally delete something, you can easily recover your files.
The easiest way to back up is to set up Time Machine, which backs up all the information on your Mac automatically every day. See Back up your files with Time Machine.
Besides Time Machine, you have several other choices for backing up your important files, including burning CDs and DVDs, and copying files onto an external drive. See Ways to back up or protect your files.
Limit unwanted access to your information
macOS has a number of features to help keep the information on your Mac safe. If multiple people use your Mac, you should set up a user account for each person so that one person can’t modify the files needed by another. See Set up users, guests and groups.
Use secure passwords to prevent unauthorised access, make sure all user accounts have passwords, and turn off automatic login in Users & Groups preferences. See Tips for creating secure passwords.
To open Users & Groups preferences, choose Apple menu 
Open Users & Groups preferences for me
For more information about keeping your information secure, see Set up your Mac to be secure and Guard your privacy.
Install software updates promptly
Your Mac is already set up to automatically check for software updates and to alert you when updates are available for you to download. The best way to avoid viruses and other problems is to promptly download and install these updates, which contain the latest security software.
To see if you have available updates, choose Apple menu
For more information about updating your software, see Keep your Mac up to date.
If nothing happens when you check for updates, you may not be connected to the internet. See Solve Internet connection problems.
Locate a lost Mac
You can use the Find My app to locate or deactivate a lost Mac from a web browser or an iPhone, iPad or iPod touch. See Set up the Find My app to locate a missing Mac.
Avoid harmful software
Malicious software, or malware, is a threat to all computer users, especially those connected to the internet. See Protect your Mac from malware.