The interface provides controls for settings such as memory limits and file-upload limits, and it may offer an editor for additional directives. Which changes are available and where they apply depends on the account's permissions, PHP handler and hosting configuration.
Changing a PHP setting is not the same as updating the PHP interpreter. In a security incident, a vendor may recommend a temporary configuration mitigation, but adjusting a directive does not prove that the underlying PHP vulnerability has been corrected.
Configuration scope matters. A setting chosen for one domain may not apply to another, and the command-line runtime can read different files from web-serving PHP. Some directives also require a process reload or another activation step.
Before changing a setting, identify the affected handler and confirm the directive is supported there. Test the application afterward, document any temporary mitigation and still apply the vendor's permanent security update.