If you are the owner of the VPS or Dedicated server subscription, you shall able to view and check the PHP version from  for your domain

From WHM

  1. Login to WHM
  2. Search for MultiPHP Manager in WHM (upper left search box)

  3. Select the domain you want to search the Search Column and you could refer to the PHP version tab for the PHP version of the domain.

From CPanel

  1. Login into your CPanel account 
  2. Under General Information on the right panel, click Server Information

  3. Under the Item column, find PHP Version to know the PHP version for the domain