PHP 7.1 is available for all new and existing servers launched on the Cloudways Platform. It is available under “Settings & Packages”. In case you do not see the option to upgrade to PHP 7.1 then contact our support and they will assist you.
We strongly recommend that customers should ensure that their applications and websites are compatible with PHP 7. In addition, the applications and websites should be tested on staging areas. Once all the issues have been removed, the applications and websites could be taken live on PHP 7.1 servers.
You can read the complete article at : https://www.cloudways.com/blog/php-7-1-on-cloudways/ or just follow the Gif to Upgrade PHP version.