I am using SharePoint 2013 and i want to customize the SharePoint default list form. Is there any way to add script/style to the form in SharePoint New Experience View?.
This is not possible yet. Microsoft is currently working on it.
But you can keep customizing in the classic experience , i dont see it going away any time soon.
Update as per Patrick's comment :
This is not available on SP 2013 On premise, its right now only available on SP Online and SP 2016 after feature pack 1 update.