On the command line, run the following commands:

# Add the Remi's RPM repository.
sudo subscription-manager repos --enable codeready-builder-for-rhel-$(rpm -E %rhel)-$(arch)-rpms
sudo dnf install -y dnf-plugins-core
sudo dnf install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-$(rpm -E %rhel).noarch.rpm
sudo dnf install -y https://rpms.remirepo.net/enterprise/remi-release-$(rpm -E %rhel).rpm
sudo dnf module reset php -y
sudo dnf module enable php:remi- -y

# Install PHP.
sudo dnf install -y php