You can change the default PHP version for all new sites created in your account by accessing your Account → Settings → Sites page in the top right corner of the MyPressable Control Panel.
Find and click the Sites option on the left side menu, and in the Default PHP Version section, select which PHP version you would like all new sites to use.
Once this is updated, any new site created in your account will use that PHP version by default.
Explore our article on how to change your PHP version on a specific site in your account.