Una vez instaladas las librerias base correspondientes,
- Go to WHM -> Software -> Module Installers -> PHP Pecl (manage)
- In the box below ‘Install a PHP Pecl’ enter: imagick
- Click the ‘Install Now’ button
- Imagick will now be automatically installed by WHM on your cPanel server.
Puede ejecutar para instalar
/opt/cpanel/ea-php71/root/usr/bin/pecl uninstall imagick
Para desinstalar
/opt/cpanel/ea-php71/root/usr/bin/pecl install imagick
FUENTE:https://forums.cpanel.net/threads/imagick-pecl-refuses-to-install-for-php-7-1.654383/