You can use CloudLinux Selector to enable or disable available PHP extensions in Plesk.
1. Log in to your Plesk account.
2. In the right-hand sidebar, click on PHP Selector.
3. Click on the Extensions menu.
Note: If the Extensions page shows an error related to the native PHP version, change it to a non-native version first.
4. For enabling the extension, you will need to tick mark that option. If you wish to disable it, then unmark it, and it will be disabled.