How to pass parameter to Laravel DB::transaction()

The use keyword is what you need:

$id = 3;
DB::transaction(function($id) use ($id) {
    DB::table('users')->where('id', '=', $id)->get();
});

For PHP 7 (untested, edited as requested by the answer below):

$id = 3;
DB::transaction(function() use ($id) {
    DB::table('users')->where('id', '=', $id)->get();
});