How can I remove that grey line on the code workspace .. Image:
This is the Show hard wrap guide (Configured in Code Style options) in Editors General Appreance settings. However the PhpStorm Version is 2018.*
PhpStorm Show hard wrap guide (Configured in Code Style options) option
So you need to go disable or unmark that option to hide that vertical line. From the PhpStorm top bar menu, go to File > Settings > Editor > General > Appearance and Show hard wrap guide (Configured in Code Style options) checkbox option and unmark to disable it.