How to enable iconv on CPanel server?

The iconv API is the standard programming interface for converting character strings from one character encoding to another in Unix-like operating systems. Initially appearing on the HP-UX operating system, it was standardized within XPG4 and is part of the Single UNIX Specification (SUS).

All recent Linux distributions contain a free implementation of iconv() as part of the GNU C Library which is the C library for current Linux systems. To use it, the GNU glibc locales need to be installed, which are provided as a separate package (usually named glibc-locale) normally installed by default.

…. source : wikipedia.org

From WHM you can compile Apache with iconv :

WHM Main >> Software >> EasyApache (Apache Update)

Follow the wizard and slect “Iconv (experimental)” under PHP Exhaustive Settings and start the Apache build by using “Start Build”.