1. Open Safari.
2. In the macOS menu select Safari → Preferences.
3. Open the Extensions tab.
4. Select the check box for Kaspersky Security.

1. Open the Preferences window in Kaspersky Internet Security 18 for Mac. If you are not sure how to open the Preferences window, see this guide.
2. Go to the Browsers tab and click Get Extension.

3. Click Get Extension.

4. Follow the rest of the installation steps.

If you want to disable or delete the extension in:  

Safari

1. Open Safari.
2. In the macOS menu select Safari → Preferences.
3. Go to the Extensions tab.  
4. Clear the check box for Kaspersky Security.
5. To delete the extension, uninstall Kaspersky Internet Security 18 for Mac. For the uninstallation guide, see this article.
6. Restart the browser.

Google Chrome

1. Open Google Chrome.
2. In the upper-right corner of the browser, click   → More Tools → Extensions.
3. Go to the Extensions tab.
4. Clear the Enabled check box for the extension. 
5. To delete the extension, click .
6. Restart the browser.

Firefox

1. Open Firefox.
2. In the macOS menu select Tools → Add-Ons.
3. Go to the Extensions tab.
4. To disable the extension, click Disable. 
5. To delete the extension, click Remove.
6. Restart the browser.