Open the Settings dialog and navigate to Editor | Emmet | HTML then check the Enable abbreviation preview setting. Going forward PhpStorm will present a popup showing the expanded markup when writing Emmet abbreviations.
#23 Emmet Preview

Open the Settings dialog and navigate to Editor | Emmet | HTML then check the Enable abbreviation preview setting. Going forward PhpStorm will present a popup showing the expanded markup when writing Emmet abbreviations.