First add this line to composer.json
"illuminate/html": "~5.0"
Then do a composer update
Wait for the update to finish, then open config/app.php add this:
'Illuminate\Html\HtmlServiceProvider',
to the providers
array and this:
'Form' => 'Illuminate\Html\FormFacade',
'Html' => 'Illuminate\Html\HtmlFacade',
to the aliases
array, and be sure when you use Html in blade or wherever use it in lowercase ‘Html’ not HTML
Here is a reference link: http://thegeekyland.blogspot.com/2015/11/class-illuminatehtmlhtmlserviceprovider.html