Answers for "Root composer.json requires PHP extension ext-gd * but it is missing from your system. Install or enable PHP's gd extension."

phpoffice/phpspreadsheet[1.1.0, ..., 1.15.0] require ext-gd * -> it is missing from your system. Install or enable PHP's gd extension

composer require "ext-gd:*" --ignore-platform-reqs

gumlet/php-image-resize 1.9.2 requires ext-gd *

#php -v to get version (change to php7.2 or whatever version if needed)
sudo apt-get install php7.0-gd