Enable PCNTL Functions on a specific virtual server

SYSTEM INFORMATION
OS type and version: Ubuntu Linux 20.04.3
Webmin version: 1.984
Virtualmin version: 6.17-3

apparently, by default, and according to the documentation, some functions of PCNTL (php) are generally security disabled.

however, I need to enable all functions, which are disabled by default, on a specific virtual server.

this virtual server is configured to run php scripts with FPM.

Please, how do I enable these functions on that specific server that runs php scripts with FPM?

tks