How to change PHP version for subdomains.

- Log in to cPanel.

- On the "Files" section, click on "File Manager"

- Access to the "public_html" folder, then click on the sub-folder corresponding to the subdomain concerned.

- Create the .htaccess file if it does not exist, otherwise modify it by adding the code below:

<FilesMatch "\.(php4|php5|php3|php2|php|phtml)$">
  AddHandler application/x-httpd-php74 .php
</FilesMatch>

- Save the .htaccess file.

As indicated on the previous code, the PHP version used is 7.4, specify the PHP version you want on the line below:
AddHandler application/x-httpd-php74