print_r($request->education); //It is an array print

$str_json = json_encode($request->education); //array to json string conversion
echo  $str_json; // printing json string

print_r(json_decode($str_json)); //printing array after convert json string to array

exit; // exiting further execution to check resutls

maybe a little simpler like that

$string=implode(",",$your_array);

You can just json_decode it.

$explode_id = json_decode($request->data, true);

Also, if you're trying to do a IN() condition, you can use:

->whereIn('id', $explode_id);

As you have pivot table for roles than you dont need role_id column in your users table

public function store(Request $request)
{
$this->validate($request, [
    'name'=> 'required|string|max:225',
    'status'=> 'required',
    'role_id'=> 'required|array',
    'email'=> 'required|string|email|max:225|unique:users',
    'password'=> 'required|string|min:6|confirmed'
]);

$password = Hash::make($request->password);
// dd($request->all());

$user = new User;
$user->name = $request->name;
$user->status = $request->status;
$user->email = $request->email;
$user->password = $password;
$user->remember_token;
$user->save();

foreach($request->input('role_id') as $role)
{
   $user->assign($role);
}
// $user->roles()->sync($request->roles, false);
return back()->with('message', 'User added successfully!!');
}