If you would like to know a PHP version for your hosting account, you can do this in cPanel.
Log in to your cPanel and go to Software => MultiPHP Manager
Arrow 1 shows the default server PHP version and you can ignore this string.
Arrow 2 shows the PHP version for your hosting account’s sites.
If you need to upgrade a PHP version, it is necessary to make some changes in your WordPress admin panel primarily. If you didn’t manage or don’t know how to do that, please, apply to your hosting provider.