How to dismiss keyboard in iOS

KeyboardDismissExample.swift

import UIKit

class RegistrationViewController: UIViewController, UITextFieldDelegate {

  @IBOutlet weak var firstNameField: UITextField!
  @IBOutlet weak var lastNameField: UItextField!
  
  override func viewDidLoad(){
    super.viewDidLoad()
    configurations()
  }
  
  fileprivate func configurations(){
    firstNameField.delegate = self
    lastNameField.delegate = self
  }
  
  internal func textFieldShouldReturn(_ textField: UITextField) -> Bool {
    self.view.endEditing(true)
    return true
  }
  
}