Outdated npm version
If an outdated npm version is shown when running npm -v, check the following post on how tu clear the Bash cache: https://askubuntu.com/questions/1036278/npm-is-incorrect-version-on-latest-ubuntu-18-04-installation
PHP plugins required by Laravel and/or composer are missing
apt install php7.0-mbstring php7.0-zip php7.0-xml php7.0-curl