Step 1. Check the version of the php.
# php – v

Current version is PHP 5.4 .
Step 2. Install Remi Repository and EPEL Repository by using following commands .
# wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
# wget http://rpms.remirepo.net/enterprise/remi-release-7.rpm
# rpm -Uvh remi-release-7.rpm epel-release-latest-7.noarch.rpm
Step 3. After installing the repository, you must perform the following additional configurations.
# yum install yum-utils
# yum-config-manager –enable remi-php74
Step 4. Install PHP 7.4.
# yum install php php-opcache php-gd php-curl php-mysqlnd
Step 5. Update the packages.
Step 6. Check the version of PHP now.
# php -v

PHP has been updated to 7.4.
Thank you!!