I am stuck with nothing showing in the table view at all no title no subtitles just blank empty white screen

class ViewController: UITableViewController {
    var petitions = [Petition]()

    override func viewDidLoad() {
        super.viewDidLoad()

        //let urlString = "https://api.whitehouse.gov/v1/petitions.json?limit=100"
        let urlString = "https://www.hackingwithswift.com/samples/petitions-1.json"

        if let url = URL(string: urlString){
            if let data =  try? Data(contentsOf: url){
                parse(data)
            }
        }
    }

    func parse(_ json: Data){
        let decoder = JSONDecoder()

        if let jsonPetitions = try? decoder.decode(Petitions.self, from: json){
            petitions = jsonPetitions.results

            tableView.reloadData()
        }
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        print(petitions)
        return petitions.count
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
        let petition = petitions[indexPath.row]
        print(petitions)
        cell.textLabel?.text = petition.title
        cell.detailTextLabel?.text = petition.body
        return cell
    }

}

Instead of

if let url = URL(string: urlString){
            if let data =  try? Data(contentsOf: url){
                parse(data)
            }
        }

You should use URLSession, Data(contentsOf:) works with Bundle files.

if let url = URL(string: url) {
    do {
        let (data, _) = try await URLSession.shared.data(from: url)
        parse(data)
    } catch {
        print(error)
    }
}

Also you should mark the function async as it would download data from internet