In laravel 6 all the helper functions are removed so all the functions like str_limit, str_uuid, array_sort, array_only are not working in this version.
If you still want to use the helper functions then you can install the package using the command
composer require laravel/helpers
Or you can can do it using Laravel facade.
use Illuminate\Support\Str; $stringslug = Str::slug('My Custom String Here');