install php 7 3 ubuntu

1sudo apt install php7.3-cli php7.3-fpm php7.3-json php7.3-pdo php7.3-mysql php7.3-zip php7.3-gd  php7.3-mbstring php7.3-curl php7.3-xml php7.3-bcmath php7.3-json

1sudo apt update
2sudo apt install php php-cli php-fpm php-json php-pdo php-mysql php-zip php-gd  php-mbstring php-curl php-xml php-pear php-bcmath
3

1sudo 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

1sudo add-apt-repository ppa:ondrej/phpsudo apt-get update

1sudo apt-get install php libapache2-mod-php

1sudo apt install software-properties-commonsudo add-apt-repository ppa:ondrej/php