Guard your privacy on Mac
Privacy is an important concern when using apps that exchange information across the web. macOS includes security features to enhance your privacy and control the amount of information that’s exposed about you and your Mac over the Internet.
Use parental controls
You can use parental controls to monitor your children’s computer use, control who can contact them using email or chat, and limit their access to websites. See Set up parental controls and Check which apps and websites your child has used.
Choose Apple menu 
> System Preferences, then click Parental Controls.
Use the privacy features in Safari
Safari provides numerous features to help you control your privacy on the Internet. You can browse privately, so Safari doesn’t keep a record of websites you visited or items you downloaded. You can block pop-up windows, stop sites from storing cookies on your Mac, and more.
Control the personal information you share with apps
Location Services lets apps, such as web browsers, gather and use information based on your location. You can turn off Location Services completely, or you can select which apps can see information about your location.
Some apps may gather and use information from your contacts, photos, calendar or reminders. Some apps may access the microphone or camera on your Mac.
See the following topics:
Choose whether to share analytics information
You can help Apple improve the quality and performance of its products and services. macOS can automatically collect analytics information from your Mac and send it to Apple for analysis. The information is sent only with your consent and is submitted anonymously to Apple. See Share analytics information from your Mac with Apple.
To choose whether analytics data is sent to Apple, use the Privacy pane of Security & Privacy preferences.
Choose Apple menu > System Preferences, click Security & Privacy, click Privacy, then click Analytics.
Set up a firewall
You can use a firewall to protect your privacy by blocking unwanted network communications with your Mac. If the firewall is turned on, you can also use “stealth mode”, which prevents your Mac from being discovered by others on the web. See Use a firewall to prevent unwanted connections.
To set up and customise your firewall, use the Firewall pane of Security & Privacy preferences.
Choose Apple menu > System Preferences, click Security & Privacy, then click Firewall.