i have php 5.6 in /etc/php but not /usr/bin code example

Example 1: change php version ubuntu

$ sudo update-alternatives --config php
 or
$ sudo a2enmod php7.1(version)

Example 2: linux set default php

update-alternatives --set php /usr/bin/php7.4
update-alternatives --set phar /usr/bin/phar7.4
update-alternatives --set phar.phar /usr/bin/phar.phar7.4
update-alternatives --set phpize /usr/bin/phpize7.4
update-alternatives --set php-config /usr/bin/php-config7.4