Laravel execute where condition based on variable null or not

I am new to laravel. I want to execute my where condition if my variable value is not null. I tried the below code exactly not getting an idea of what to do.

$search = $array['search'];
$id = $array['id'];
$Data = Model::where('id', '=', $id)

if($search != '') {
    //I want to include where condition here
}

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