keyboardNotifications.swift

func registerForKeyboardNotifications() {
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWasShown(_:)), name: UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillBeHidden(_:)), name: UIResponder.keyboardWillHideNotification, object: nil)
}

@objc func keyboardWasShown(_ notification: Notification) {
    guard let info = notification.userInfo,
          let keyboardFrameValue = info[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue else { return }
    let keyboardFrame = keyboardFrameValue.cgRectValue
    let keyboardSize = keyboardFrame.size

    // set contentInset to add it on scrollView and match with keyboard height
    // contentInset is an additional blank space you can use since keyboard is overlap on you view, you create contentInset to avoid overlapping
    let contentInsets = UIEdgeInsets(top: 0, left: 0, bottom: keyboardSize.height, right: 0)
    scrollView.contentInset = contentInsets
    scrollView.scrollIndicatorInsets = contentInsets
}

@objc func keyboardWillBeHidden(_ notification: Notification) {
    let contentInsets = UIEdgeInsets.zero
    scrollView.contentInset = contentInsets
    scrollView.scrollIndicatorInsets = contentInsets
}