// 1st method

if let storyboard = self.storyboard {
            let vc = storyboard.instantiateViewController(withIdentifier: "ForgotPasswordViewController") as! ForgotPasswordViewController
            vc.modalPresentationStyle = .fullScreen
            self.present(vc, animated: false, completion: nil)
        }

// 2nd method

    func nextVC(identifier: String) {
        if let storyboard = self.storyboard {
            let vc = storyboard.instantiateViewController(withIdentifier: identifier)
            vc.modalPresentationStyle = .fullScreen
            self.present(vc, animated: false, completion: nil)
        }
    }