STEP 1 : Login to Direct Admin( Guide here )

If you have multiple domains in your account, ensure that the correct domain is selected at the top right corner. Eg. We are going to upload the files to the fastdirectadmin.com domain

STEP 2 − You can find it by typing "Select PHP" in the Direct Admin search bar, below is an image of the Direct Admin search bar, and the Select PHP Version

STEP 3 − Click on the drop down arrow beside the PHP Version like shown below

STEP 4 − Select a PHP Version you desire. In this example, we are using PHP 7.2

STEP 5 − Click set as current.  If everything is succesful, you will see that the current PHP Version no longer shows native, but shows the PHP Version you chose ( In this scenario, PHP Version 7.2 )

STEP 6 -  ( Optional ) You can install/uninstall PHP Modules by ticking/unticking them on this page too