ios – How to place a button to the center of navigation bar?


I am trying to place a clickable info button showing a message and body close to the navigation title name. I have created a function that will show the message however it isnt place on the center of the navigation controller. How do I fixed this ?
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 func tooltip(body:String, title:String, titleSize:CGFloat, bodySize:CGFloat ){

         let alertController = UIAlertController(title: title,message: body, preferredStyle: .actionSheet)
        let titleAttributes = [NSAttributedString.Key.font: UIFont.boldSystemFont(ofSize: titleSize)]
        let titleString = NSAttributedString(string: title, attributes: titleAttributes)
        let messageAttributes = [NSAttributedString.Key.font: UIFont.systemFont(ofSize: bodySize)]
        let messageString = NSAttributedString(string: body, attributes: messageAttributes)
        alertController.setValue(titleString, forKey: "attributedTitle")
        alertController.setValue(messageString, forKey: "attributedMessage")
        let popover = alertController.popoverPresentationController
        popover?.sourceView = self.view
        let button = UIButton()
        button.setImage(UIImage(systemName: ""), for: .normal) =
        popover?.sourceRect = button.frame
        popover?.permittedArrowDirections = .any

        self.present(alertController, animated: true, completion: nil)

   private func setupNavigationItem() {
        self.title = self.viewModel.filter.label
        switch title{
        case "Last Visit":
                    tooltip(body: """
                      XXXX \n
                      XXXX \n
                     XXXX \n
                     XXXX \n
                     XXXX \n
                     XXXX \n
                  title: "The Last Visit filter includes:", titleSize: 14.0, bodySize: 15.0)

        navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Done", style: .plain, target: self, action: #selector(donePressed))