Step1: Navigate to Tools & Settings > Updates.
Step2: Open the Add/Remove Components tab.
Step3: For Plesk on Linux, expand the Web hosting section and locate the PHP interpreter versions section. For Plesk on Windows, expand the Plesk hosting features section.
Step4: Identify installed PHP versions by the green checkbox icon and uninstalled versions by the red cross icon.
Step5: To install a PHP version, click the corresponding icon > Install.
Step6: To remove a PHP version, click the corresponding icon > Remove.
Step7: Review your selections in the screenshot. In the example, PHP versions 7.3, 7.2, and 7.1 are marked for installation, while PHP versions 7.0 and 5.6 are marked for removal.