Step 1 – Install PHP

# sudo apt-get update

# sudo apt -y install software-properties-common

# sudo add-apt-repository ppa:ondrej/php

# sudo apt-get update

# sudo apt -y install php7.4

# sudo php -v

You will receive something similar to the following:

Step 2 – Required PHP-7.4 extensions For Magento 2.4.x

# sudo apt-get install php7.4-curl
sudo apt-get install php7.4-zip
sudo apt-get install php7.4-xsl
sudo apt-get install php7.4-soap
sudo apt-get install php7.4-simplexml
sudo apt-get install php7.4-mbstring
sudo apt-get install php7.4-iconv
sudo apt-get install php7.4-dom
sudo apt-get install php7.4-ctype
sudo apt-get install php7.4-bcmath
sudo apt-get install php7.4-intl
sudo apt-get install php7.4-gd
sudo apt-get install php7.4-mysql
sudo apt-get install php7.4-xmlwriter
sudo apt-get install php7.4-sockets
sudo apt-get install php7.4-json

Know More:

How To Install Elasticsearch On Ubuntu