How to enable/disable PHP extensions in Plesk?
To enable/disable PHP extensions on a server-wide level go under Plesk > Tools & Settings > General Settings > PHP Settings > choose the required PHP version > Extensions tab.
You can find the description of each extension in PHP documentation.
Note: In case if there is no the required extension in the list, it means that the extension is not installed on the server and it is required to install it manually.
How to add additional PHP module for PHP engines shipped with Plesk on Linux?