install php ubuntu 20.04

C++
sudo apt update
sudo apt install php7.4
sudo apt install php7.4-common php7.4-mysql php7.4-xml php7.4-xmlrpc php7.4-curl php7.4-gd php7.4-imagick php7.4-cli php7.4-dev php7.4-imap php7.4-mbstring php7.4-opcache php7.4-soap php7.4-zip php7.4-intl -ysudo apt install software-properties-common
sudo add-apt-repository ppa:ondrej/php

sudo apt update

sudo apt install -y php7.4sudo apt install php7.1 php7.1-common php7.1-opcache php7.1-mcrypt php7.1-cli php7.1-gd php7.1-curl php7.1-mysql
Source

Also in C++: